Popular Science Monthly/Volume 66/April 1905/The Bermuda Islands and the Bermuda Biological Station for Research II
|THE BERMUDA ISLANDS AND THE BERMUDA BIOLOGICAL STATION FOR RESEARCH. II.|
By Professor EDWARD L. MARK,
DIRECTOR OF THE ZOOLOGICAL LABORATORY OF HARVARD UNIVERSITY.
BEFORE speaking about the life in the seas I wish to say a few words about the Bermuda Marine Laboratory. Not very long after my conversations with President Eliot, and when I was considering ways and means of providing an opportunity for students to work at Bermuda, I had the good fortune to make the acquaintance of Professor Bristol, and hear from him for the first time a glowing account of his experiences of several years, and his plans and hopes regarding a somewhat similar undertaking. Our aims had so much in common that cooperation seemed desirable to both of us, and we at length agreed to undertake, with the aid of the Bermuda Natural History Society, to equip and manage a provisional laboratory, which might serve till such time as the colonial government should be able to put at the disposal of biologists a permanent station. Chiefly through the enthusiastic interest of Dr. Bristol, in cooperation with the Bermuda Natural History Society, the colonial government had been led to entertain the idea of establishing a public aquarium for the enlightenment and amusement of people resident in the islands as well as the tourists, and in connection with it a marine laboratory for biological investigations. A joint committee of the Legislative Council and the House of Assembly, consisting of Sir S. Brownlow Gray, chief justice, Hon. Eyre Hutson, colonial secretary, and assemblymen J. H. Trimingham, Nathaniel Vesey and A. Gosling, was appointed to consider the advisability of establishing such a station, and in due time reported favorably on the undertaking. The governor, Lieut. General Geary, at the suggestion of the committee, entered into correspondence with many institutions and individuals in both Europe and America, with a view to ascertaining their opinions as to the desirability of establishing such a station and the possibility of their cooperation. The replies were all favorable, and a certain amount of support was promised. Early in 1903 Professor Bristol and I were invited by the Natural History Society to visit Bermuda for the purpose of looking into the conditions and giving advice with regard to the general plan and certain matters of detail. This we did toward the end of April. Upon our return, and after the money necessary for the undertaking had been secured, we issued to biologists in the name of the Bermuda Natural History Society and the universities which we represented an invitation to share for six weeks in the privileges of a temporary biological station at the Flatts, Bermuda. The generosity of the Natural History Society and the liberality of our friends allowed us to provide ample means for collecting and all the requisites for laboratory work, except that we had no running water in the laboratory. The building, however, was only a short distance from the sea, so that this deficiency was not very serious.
Through the favorable terms for transportation secured from the Quebec Steamship Co., and for board and lodging at the Hotel 'Frascati,' it was possible to make the cost of staying six weeks at the station, together with transportation from New York and back, only
one hundred dollars. Thirty-seven persons availed themselves of this opportunity, and of these thirty-three were engaged in the study of zoology or botany, four being companions of one or another of those who were working in the laboratory. Of these thirty-seven persons about a dozen sailed from New York on June 20, the remainder two weeks later. Arriving in Hamilton, the party was met on board the steamer and welcomed by Archdeacon Tucker, president of the Bermuda Natural History Society; U. S. Consul, W. Maxwell Greene, vice-president; F. Goodwin Gosling, honorary secretary, and other members of the society. A carriage ride of four miles over Mt. Langton and along the north road—from which one gets magnificent views of the great north lagoon and its ever-changing brought the party to the Flatts and the hotel. The Flatts village (Fig. 13) centers at the cross-roads near the bridge which spans the narrow passage from the Inlet into Harrington Sound. It contains the hotel, the post office, a half-dozen shops, and one or two scores of dwellings, which range in size and attractiveness from 'Palmetto Grove,' the home of Archdeacon Tucker, to the twenty-foot cottage of the unambitious colored family. On nearing the Flatts the north road runs along the hillside that rises to the south of the Inlet, gradually descending to sea level, at the corners, where it meets the middle road. The cottages are scattered over this hillside, which looks out on Harrington
Sound and affords at many spots beautiful views of that land-locked sea and the wooded heights beyond. The hotel (Fig. 14) is located on a low projection of land that makes out into the Inlet from its south shore and commands on one side a view of the sea (Fig. 15), on the other a view into Harrington Sound. It consists of half a dozen buildings; two of stone (one built as a residence many years ago) placed gable to gable and facing the water; a much newer wooden structure, which, with its broad piazza, projects out over the clear waters of the Inlet; the kitchens and a storehouse behind the older buildings; and, lastly, a new stone building some forty feet square located back of the wooden one, between it and the public road. This building we rented for a laboratory (Fig. 16); it had been divided up by light partitions into several rooms, and proved to be fairly well adapted to our needs. The laboratories were furnished with substantial work tables, having ebonized tops and banks of drawers. A library of specially selected books and pamphlets from the libraries of the Museum of Comparative Zoology, the Boston Society of Natural History, and the writer, several hundred in number, was arranged in the largest workroom. An ample supply of glassware, reagents and preservatives, dissecting lenses, microtomes, paraffin imbedding appliances and all the other usual equipment of a zoological laboratory were provided, as well as the necessary appliances for collecting, such as dredges, nets, seines, tubs,
buckets, sieves, water glasses, et cetera, so that few wants were felt in this direction by any of the party. The number of students was, however, so large that the laboratory building was inadequate for the accommodation of all. When the second party arrived, therefore, a large ground-floor room in one of the stone buildings of the hotel was fitted up with portable tables for those who had less need of appliances for microscopic work.
Very satisfactory means of transportation to collecting grounds, both by land and by water, were provided. For places not readily accessible by boats, wagonettes and carriages were furnished, and those who collected land plants made much use of them. Several persons had brought with them their bicycles and thus were less dependent on the organized parties. Regular excursions were arranged for nearly every day, except Sundays; frequently two in a day, and sometimes two by sea and one by land. As far as practicable shore collecting and coral 'nipping' on the reefs were planned for the low-tide hours of the day and dredging for other times.
One of the places most frequently visited by land conveyance was Hungry Bay, on the south shore nearly opposite Hamilton. The entrance to the bay is narrow and rocky, yet a great variety of animals are blown in by the southerly winds, and the place has thus become a rich collecting ground. The loose and porous rocks just inside the
entrance on either shore afford hiding places for great numbers of worms and other invertebrates. Upon turning over these rocks the bottom seems alive with creatures of many kinds. Only half the booty is seen, however, unless the rocks are broken into fragments. Thus are set free boring mollusks, annelids and many other forms that find protection, or a lair, in the holes and tortuous passages of this porous, honeycombed limestone.
In many places the floor of the shallower parts of the bay is covered by a large tubularian hydroid, in others, where the current is stronger, by great yellowish or greenish patches of colonial actinians (Palythoa) belonging to the Zoanthidae (Fig. 17). The upper end of this bay is a swamp of mangroves (compare Fig. 18), on the branches of which numbers of tree crabs (Goniopsis cruentatus) clamber about. To catch these creatures requires some skill, two persons usually succeeding better than one, for the crab, when too closely pursued, quickly drops to the ground, even from a height of ten or fifteen feet, and escapes into a burrow, unless a net is dexterously interposed during his descent. Along the edges of the tidal stream near the head of the bay are found in great numbers prawns that are so transparent as to escape observation until they move; they dart about with such swiftness that it is difficult to take them in the net.
When one cautiously approaches the edge of the cliffs that flank the entrance to the bay and looks down on the hard, wave-beaten rocks he sees large numbers of crabs that take alarm at the least motion and scurry away to crevices, or scramble down into fairly deep water, where with their sharp claws they are able to cling to the rough rocks and make almost as good progress as in the air. On the platforms and in the niches of the rock between tide marks are congregated hundreds of chitons (Chiton marmoreus), whose shells give proof of the action of the waves, which are almost constantly dashing against them at high water.
In view of the possibility of the establishment of a permanent station, it seemed desirable to keep records of the places where various animals and plants were found. To this end each person was provided with a note book, and to prevent duplication of locality numbers, certain locality numbers were assigned with each book. Whenever a party of individuals made collections together in a circumscribed area, as in dredging, or in shore collecting at particular spots, the same locality number was used by all. To enable future workers to find the precise localities mentioned, these places were designated by latitude and longitude. Fortunately for this plan there had been recently published an Ordinance-Survey map of the Bermudas on a scale of 880 feet to the inch, so that by ruling one of these maps with rectangles ten seconds square it was possible to indicate on the map the position of any locality to within a very few feet.A card catalogue embracing the names of all the animals and plants arranged systematically will ultimately show, not only what organisms, both living and fossil, are to be met with in the islands and adjacent waters, but also the precise localities at which they have been found, and the conditions under which they live. To this will be added as rapidly as possible the periods of ovulation, etc., so that one may not waste time in searching in the wrong place or at the wrong time of year for the material one needs.
Fig. 17. Palythoa grandiflora. A Group of Living Animals. Natural Size.
Fig. 18. Walsingham Bay. Mangroves and, in the Background, Cedars. Photograph by W. O. Van Name.
* Figures 17, 19-23 and 27 are from photographs by A. Hyatt Verrill.
In the immediate vicinity of the laboratory—in the Inlet and in Harrington Sound—are found an abundant supply of many interesting animals. From the stone pier at the hotel are to be seen great numbers of brightly colored fishes: the yellow-banded sergeant majors (Abudefduf saxatilis), sea squirrels (Holocentrus ascensionis), so called on account of the bigness of their eyes, angel fishes (Angelichthys ciliaris), four eyes (Chætodon bimaculatus) and many others. The large eye-spots of the four-eyes at the tail end of the body evidently afford protection by misleading their enemies into the belief that they will attempt to escape in a direction opposite that in which they actually swim. Schools of blue fry and other small fishes pursued by their enemies make a flash in the sunlight as they leap from the water and a sound like the patter of rain as they descend. Small shoals of white grunt (Bathystoma), that so closely resemble the sandy bottom as to be almost invisible, are slowly patrolling along the beach and often attract one's attention only when their presence causes a commotion among their prospective victims.
The water is so clear that the bottom at a depth of fifteen or twenty feet is seen as distinctly as it would be beneath as many inches of our northern waters. Along the sandy stretches of the inlet, where the current is not too strong, are numerous dark sea-urchins (Toxopneustes variegatus), which have the interesting habit of covering themselves with empty shells, seaweeds or any loose available fragments. Just what sort of protection these screens afford is not quite apparent. To the observer looking from above they are scarcely less conspicuous than when unadorned. Their specific form and characteristic color, it is true, are masked, and possibly this is enough to subserve some useful purpose. By digging a few inches deep in the sand at the right spot one brings up another echinoid, the sand-dollar (Mellita sexforis). Scattered over the bottom are the apparently motionless but conspicuous sea-cucumbers, which the natives call sea-puddings—the Stichopus diaboli and S. xanthomela of Heilprin. These often attain the length of a foot or more and leave behind to mark the track of their slow progress a cord or ridge of sand that has been deprived of its nutritive material in passing through their intestinal tract. These are abundant on many sandy bottoms; other holothurians are less widely distributed. In the shallow parts of the Inlet, which are laid bare at low tide, are the burrows of many annelids and other worms. Where the channel is rocky and the water moves with greater velocity the bottom is often gorgeously painted with patches of bright-colored corallines and encrusting sponges. Opposite the hotel an artificial channel cut through the narrow neck of land that separates the Inlet from Harrington Sound is of this nature and affords a rich collecting ground for many invertebrates. With a row boat and a good water-glass one may study with, delight the shores of Harrington Sound and its numerous coves and get beautiful views of the delicate shade-corals (Agaricia fragilis, Fig. 19), the many kinds of sea anemones (Figs. 20, 21, 22) and the sponges, which abound there. Collecting is easy and the variety of life great. Occasionally the long 'whips' of the Bermuda lobster (Panulirus argus) are seen projecting out of some cervice in the rock, as he lies in wait for his prey. If less palatable than our American lobster, the Bermudian has a more graceful form and a much handsomer livery (Fig. 23).
In addition to a thirty-foot sail boat with its glass-bottomed fish well, such as the native fishermen use, the station was furnished in the summer of 1903 with a steam launch (Fig. 21) some 35 feet long, the Minnow. For three fourths of her length she had a light wooden deck and side curtains, which could be lowered to keep out sun, rain or spray. Her pilot house was low, but roomy, and served as a forward cabin as well as wheel house. In this launch almost daily excursions were made to various parts of the archipelago, according as the conditions of wind and tide favored this or that locality. For all purposes except that of dredging she was well suited to our needs, for, being of light draught, she could be used about the shoals and flats with safety and ease.
I recall with pleasure not only my own fascination, but also the
expressions of delight which involuntarily came from the lips of all who, with water-glass in hand, peered down into the fairy-like gardens of the sea, as we slowly drifted with the tide or lay at anchor in the midst of one of the great coral patches that flourish over extensive
|Fig. 21. Anemonia elegans, Verrill. X 11⁄4||Fig. 22. Phillia rufa Verrill. X 1⁄2|
areas of the north lagoon. I confess the pleasure was so great that the spirit of the collector was suppressed for the time being; it seemed sacrilege to touch with violent hands a picture that showed such harmony of form and color—the waving plumes, the graceful branches of the gorgonias; sea fans in purple splendor; coral heads of gold and green; great splotches of colored sponges encrusting the rocks; the soft seaweeds; here and there deep channels with nothing but the clear water and the white sand beneath it; and in and out among this maze of growing things, the graceful, noiseless fishes in such array of colors as is scarcely credible, much less describable. I believe it may be truly said that one who has never seen such a tropical sea-garden
can not have the remotest idea of its charm. There was only one consideration that could reconcile me to the wanton work of collecting these beautiful things and robbing them of all their native charm; that was the fact that, work as diligently as we might, we could not deface one in a thousand of these fascinating spots. I think there is no other single experience I would willingly exchange for this; and yet I recall one other, of a somewhat different nature, that made a strong impression on me. As three of us were out one afternoon off the south shore beyond the reefs fishing in about sixty fathoms, there came floating past with the tide a school of jelly fishes, the common Aurelia. I had before seen Aurelia almost cover the surface of the sea, but never before had I been able to look down, as then, and see them in the depths of the sea. They were seemingly without end, a vast procession, smaller and smaller the deeper one gazed, until they seemed mere specks, such was the clearness of the water.
For use in dredging a much larger steamer (Fig. 25), the Intrepid, was for a part of the time at our command in place of the Minnow. This steamer was provided with a boom in front of the pilot house, which much facilitated dredging operations, and the forward deck was
a convenient place for inspecting the dredgings, assorting tows, etc. This was the steamer that had been employed by Mr. Agassiz during his explorations in 1894. With her we made, besides other excursions, several trips to North Rocks (Fig. 26)—three sole survivors of a land mass that doubtless extended in previous times along the northern border of the lagoon, as the present land area now does along its southern rim. It is only on the calmest days and at lowest tide that one may safely land on the plateau from which these three pinnacles, called North Rocks, arise. The steamer can approach within a half or a quarter of a mile and then must anchor, while in rowboats the collectors make their way to this sea-washed platform. On the sea face the rock, which is an æolian limestone, is slightly raised above the general level of the floor, and is overgrown with nullipores and other corallines,
as well as non-calcareous algæ; and here serpulas, millepores and porites abound. Even at low tide this rocky platform is barely above water, and it is so honeycombed and porous that its surface is very
irregular. The flatter portions are covered here and there with patches of the curious Zoanthidæ. There are innumerable pools and channels all showing the greatest variety of color in the plant and animal life that clothes their sides and bottoms. Here in the pools and passages, is a greater wealth and variety of life than can he found in an equal area elsewhere in all the Bermuda archipelago. Located on the very edge of the outer reef, where breakers are always running, save in perfectly calm weather, the conditions seem to be especially favorable for many of the marine organisms. Numerous small and brilliantly colored fishes dart about in the pools, and escape into the crevices of the rock as one attempts to scoop them up. The great black sea-urchin (Diadema setosum) bristling with slender spines is firmly ensconced in niches in the rocky floor and usually defies all attempts at removal. But by breaking away the rim of protecting rock this urchin may sometimes be dislodged. Unless great care is used, however, his spines, which are like needles, will penetrate the flesh, where they are sure to break off and become a source of great irritation if not promptly removed; but they are so brittle that removal is not an easy matter. Crabs both great and small are everywhere, and the little hermits with their molluscan shelters of various kinds and sizes make a grotesque appearance as they scuttle away to cover.
One of the most novel sights that I saw in these tropical seas was viewed through a water-glass near North Rocks. A school of small fishes (Atherina) swimming in a nearly spherical mass ten or fifteen feet in diameter, seemed to be slowly revolving through the water as its individuals swam round and round in an almost solid mass. It was not at first apparent how the mass preserved such a constant form, but at length it was seen that a few individuals of another and larger species of fish were acting the part of the shepherd dog, and that the smaller fishes were actually being herded—a flock of submarine sheep. Nor do the herding fishes prey upon their flocks. The explanation is interesting. Three kinds of fishes are involved in this association. The herders accompany and ‘round up’ the smaller fishes, so that other kinds of fish which are wont to prey upon them may, as they approach with murderous intent, fall victims to the herders.
Picturesque Castle Island, which still contains ruins of early fortifications,—some of them possibly dating from the early part of the seventeenth century,—once guarded the entrance from the sea through the channel of Castle Roads. From the floor of this channel the dredge brings up many interesting animals: the great conchs (Strombus gigas), the shells of which are still prized by tourists, living Foraminifera of several kinds, and, best of all, the Caribbean Amphioxus. This species was dredged in considerable numbers at various places during the summer of 1903, and especial attention was given during the past summer to finding out how widely it is distributed, and the conditions under which it thrives. As a result we now know that there are ten or a dozen localities where it is found in large numbers, and that a fairly coarse clean sand and strong currents of clear water are conditions that it generally seeks. The peculiar odor, resembling that of iodine, which is a noticeable feature of the 'Amphioxus sand' in the Bay of Naples, was not recognized at any of the collecting places examined by us. Incidentally in our dredgings for Amphioxus, it was noticed that there are many sandy bottoms and beaches which are inhabited by large numbers of a rather small Balanoglossus. The western portion of Castle Harbor contains brain corals (Meandra) in great abundance, many of them attaining an enormous size and weight. The rocky shores, overgrown with encrusting sea-weeds, are a favorite browsing place for the great opisthobranch mollusks (Aplysia), which the Bermudians call sea-cats (Fig. 27).
Off the south shore, at a distance varying from a few rods to a quarter of a mile, runs a rocky ledge,—a kind of barrier reef,-—over which the sea is breaking incessantly. Here and there the rocks take on the form of a huge bowl or crater (Fig. 28), from the rim of which the water pours over after each swell of the sea in a beautiful cascade. These diminutive atolls are known locally as 'the boilers.'
During almost every excursion through the northern lagoon there were encountered extensive patches of floating gulf weed (Sargassum), which, I may mention, grows at certain points along the south shore. An examination of the larger masses almost always yielded an abundance of various crabs, bryozoans and nudibranchs, some of the latter being most beautifully colored; frequently the less common fishes, such as the pipe fish (Syngnathus) and the grotesque Antennarius, were found in these floating islands, evidently their natural home. After protracted strong winds there are thrown upon the beach long windrows of gulf weed, which harbor a variety of the animals that live on the open sea. At such times the Portuguese man-of-war (Physalia) is frequently so abundant as to make the beach purple with its floats. Through the generosity of Captain William E. Meyer, of St. George's, a three-days' trip to the Challenger Bank was arranged for all the members of the station who desired to go. Captain Meyer put at our disposal his seagoing steam tug, the Gladisfen, and her crew. Many hauls of the dredge were made and rare corals, Crustacea and other invertebrates secured. The edge of the bank is an ideal fisherman's ground, abounding in redsnappers (Neomæius aya) and amber-fish (Seriola dumereilii). As might be expected, sharks, too, are found there in abundance.
Some of the investigations undertaken by us have already been published as 'Contributions' from the station; others are in press or in course of preparation. Mr. Leon J. Cole's paper on the Pycnogonida (Proc. Bost. Soc. Nat. Hist., Vol. 31) contains an illustrated description and critical discussion of three species, one of which is new. Mr. Addison Gulick has described (Proc. Acad. Nat. Sci. Phila., Vol. 56) some twenty-five species of fossil shells—seven of which are new—from a number of localities, and has pointed out their relationships to shells of Eastern North America and the West Indies. Notes on birds seen during July and August have been published by Mr. Harold Bowditch (Amer. Nat., Vol. 38). Professor Coe, of Yale University, has published an important paper on one of the very interesting land nemerteans: ‘The Anatomy and Development of the Terrestrial Nemertean (Geonemertes agricola) of Bermuda’ (Proc. Post. Soc. Nat. Hist., Vol. 31).
Among the other subjects for which material was collected, or upon which investigations were carried on, are the following: The internal parasites of fishes, fossil vertebrates, new marine fishes, shoal-water deposits, land mollusks, insects, myriapods, annelids, land planarians, bryozoans, acalephs and hydroids, foraminifera, diatomaceous earth, marine plants, and the conditions of swamp formation.
During the past summer we had the use of the steam launch Flora, owned by Mr. Henry H. Barton, of this city. This launch was larger (about 45 feet over all) and in many ways better than the Minnow. This year we were fortunate enough to find at several localities a near relative of Amphioxus—the interesting Asymmetron, which was discovered several years ago at the Bahamas by Professor Andrews, of Johns Hopkins University. This was first recognized at Bermuda by Mr. Louis Mowbray, of St. George's, who was a member of the station party. It is an interesting fact that, so far as our search extended, Amphioxus and Asymmetron do not inhabit the same sand banks. The Bermuda Asymmetron is much smaller than Amphioxus and much more expeditious in burrowing into the sand. Amphioxus is remarkably quick in its movements, but Asymmetron is quicker. The habits of these two primitive vertebrates, as well as the finer anatomy of their nervous systems and the anatomy and physiology of other organs, were studied by members of the party this year, and will form the basis of special papers to be published later.
In conclusion, I wish to state that the Bermuda government has decided to erect a permanent Aquarium and Biological Station at the Flatts, in accordance with the plans that I have already referred to, and has voted a sum of money (about $20,000) for the undertaking, and a smaller annual sum ($2,000) for its maintenance. It is expected that when the buildings are completed arrangements will be made to have the station open for research throughout the year.