A HISTORY OF STAFFORDSHIRE Family Cyclopidac. Cyclops quadricornis (Mtlll.). The Four-horned Cyclops or Lesser Water Flea. This species swarms in water that is at all stagnant. I have known it to make its appearance in an elevated roof water-cistern a very few months after the cistern had been made. The eggs must, apparently, have been conveyed to the roof either by rain or wind. Order Rotifera. This order, which consists of interesting microscopic forms of life, has generally been classed with the Infusoria : but the organization of the Rotifera shows clearly they naturally be- long to the Crustacea, and that they follow the Entomostraca in a lineal series. The species of this order are not numerous in the district, but Rotifer vulgaris (Ehr.), the Common Wheel Animalcule, is very abundant in the dirt that accumulates in spouts and in roof-gutters, and it is a most pleasing object for the microscope." So full and intelligent an account of the Crustacea is quite exceptional in the faunistic catalogues of inland districts at the date when the above report by Mr. Edward Brown was published. That it should now in some points be open to criticism is in no way a reproach, but the natural consequence of such progress as science has happily been making in the interval. Thus, to begin with, the systematic position of the rotifers, as at present accepted, while ranking them far above infusorians, by no means gives them admission into the class with which we are here dealing. There is a vast group or phylum of animals to which Sir E. Ray Lankester has applied the term Appendiculata, because their more or less segmented bodies are capable of bearing on each body-segment a pair of hollow lateral append- ages or parapodia moved by intrinsic muscles and penetrated by blood-spaces. The phylum is divided into three sub-phyla, respectively called Rotifera, Chaetopoda, Arthropoda. See- ing that the Chaetopods or true worms are interposed between the first of these groups and the Arthropoda, with jointed legs, to which the crustaceans and other important classes belong, the relationship between a rotifer and a shrimp is evidently very remote. In the general history of animals this relationship is not to be disregarded, but it will not justify the inclusion of creatures so very distinct in one and the same class. The genera and species mentioned by Mr. Garner and Mr. Brown are not very numerous, compared with the whole number which will beyond doubt be eventually found within the waters of Staffordshire. But few as they are, they fortunately spread themselves over most of the chief sections of the class likely to be represented in the district. Any one, therefore, who made himself acquainted with these examples alone would lay the foundation for a very complete mastery of the whole subject. He would have to do, however, only with two of the sub-classes, the Malacostraca and Entomostraca, and in the former he would make no intimacy with the stalk-eyed, ten-footed, short-tailed, true crabs, the Brachyura. This highly organized group might be inclined, after Dr. Plot's example, to lump together almost all other crustaceans as being in comparison with their own intelligent selves mere brutes. In the tropics they have indeed some worthy competitors among the Macrura anomala. But none of the specially gifted land crustaceans have been attracted to our uncertain climate. In the central parts of England the highest representative of the class is the podophthalmous, macruran decapod, already often mentioned, Potamobitu pallipes. This is included with the lobster in the tribe Astacidea, but belongs to a separate family, the Potamobiidae. As being podophthalmous the river crayfish shares with an endless variety of crabs, lobsters, prawns, and shrimps, the peculiarity of having its eyes on movable stalks or peduncles. The theory is that the organs of vision have been developed on the pair of appendages pertaining to the first body- segment, although in almost all cases the segment itself has become immovably fused with the segment behind it. Also in common with the animals classified in popular speech under the four names above given, the crayfish is a decapod. Its ten feet are distributed in pairs to the body-segments numbered from the tenth to the fourteenth. The Malacostracan body is composed of twenty-one segments, each of them, with doubtful exception of the last, being endowed actually or potentially with a pair of appendages. More or fewer of these are called feet, according as they show more or less plainly an analogy with the legs and arms of verte- brate animals. From crabs the crayfish is separated by being macrurous or long-tailed. Yet in both the tail or pleon consists of the last seven body-segments, from the fifteenth to the twenty-first. But somehow, apart from the question of length or shortness, an additional distinction has arisen, that, while in the genuine Macrura the last segment but one always carries a pair of appendages, this pair is always wanting in the genuine Brachyura. The drop in dignity is rather abrupt from the only stalk-eyed decapod which our inland counties possess to the Edriophthalma tetradecapoda, or sessile-eyed, fourteen-footed Malacos- 11 Op. cit. (1863), p. 132. 128
