The Zoologist/4th series, vol 2 (1898)/Issue 681/Notes on British Annelids

by Hilderic Friend

 

NOTES ON BRITISH ANNELIDS.

By Rev. Hilderic Friend.

 

I. Distribution of Tubifex.

In nearly all old lists in which records are found we meet the two entries, Lumbricus terrestris and Tubifex rivulorum. Under these two names were included respectively all the common species of Earthworm, and all the usual bloodworms of ponds, ditches, and streams. As the old Lumbricus group has been worked out, new genera and species have been differentiated, so that to-day it would be inadmissible to make an all-round entry under this heading; similarly with Tubifex. Much has been done of late years by a few English specialists, and more by continental workers, to extend our knowledge and analyse results. The term Tubifex is now used not only in a generic sense, but has been raised to the rank of a family, under which nearly twenty well-defined genera are grouped. The difficulty at present is to know to what genus or species the old records are to be assigned. Evidently the only way to settle the matter is by making an accurate entry every time any one or other of the Tubificidæ is found. Having examined a good many specimens from various parts of England and Ireland, I think it may be well to place on record here the localities and species about which no question can exist. I do not profess to give a complete list of all the species I have myself examined, nor do I include habitats recorded by Benham and others; but simply put down a few indisputable items as a nucleus around which further records may gather as research extends. I have undoubted records from the following places of—

1. Tubifex rivulorum, Lam.—Gasworks, Idle, near Bradford, and banks of Aire around Apperley, Yorks; dykes at Pevensey and ditches at Dallington, Sussex; banks of Derwent and muddy backwaters around Cockermouth, Cumberland; Ocker Hill, Tipton, Staffs.

2. Limnodrilus udekemianus, Clap.—Received from Ballintoy, Ireland, and reported in 'Irish Naturalist,' 1897.

3. L. wordsworthianus, Friend.—A species new to science found by myself in a pond at Old Carlisle, Wigton, Cumberland. It lives in mud at roots of plants, and when taken coils up as Tubifex does. When examined under the microscope the absence of capilliform setæ at once shows it is not Tubifex, while the fact that it has more than two setæ in each anterior bundle differentiates it from Stylodrilus, a worm which is moreover readily distinguished by its appendant penis. The worm is from two to three inches long, but owing to its habit of coiling up is very difficult to measure. Four to six forked setæ are found in each of the front bundles. The blackish chloragogen cells begin in segment v. These cells often become detached and float in the cœlomic fluid. They are globular, and when injured burst and dissolve into a thousand tiny specks. The first nephridium lies in segment vii. Dilated hearts in viii-ix. The tail, as in most Tubificids, lighter in colour than the rest of the body. A pair of trumpet-shaped penis-sheaths about four (or five) times as long as broad. In the living worm the brain appears almost circular, or like a square with the two hindmost angles rounded off. It changes in appearance, however, with every new movement of the worm. Eggs were found in as many as six segments or more. A remarkable feature is found in the delicate papillæ with which the peristomium and fore part of prostomium are covered. I have named it after the poet, because I had the honour to be President of the Wordsworth Institute (in his birthplace) when the worm was discovered.

4. Hemitubifex benedii (D'udekem).—Received from Malahide, Ireland.

5. Branchiura sowerbii, Beddard.—Since Mr. Beddard reported this beautiful worm from the tank in Regent's Park, I have received specimens from Mr. Nicholson, taken in tanks from Kew Gardens, March, 1897.

I have also records for certain species of Psammoryctes and Hyodrilus, but as they are either new to science or still under investigation, the localities will for the present be held in reserve. As to habitats, it seems almost impossible to examine the wrong place if water and mud are present. The worms, however, have a special liking for ooze, vegetable and animal remains in a state of decay, the fœtid banks of streams in manufacturing districts, and similar spots. I should be glad if correspondents would supply me with gleanings from such like situations for further record.

 

II. British Enchytræids.

During a recent flying visit to Yorkshire I took occasion to visit a spot on the banks of the Aire at Apperley where I have often in former years found valuable material. The time of year was not favourable, as the worms had gone into winter quarters. I was fortunate, however, in finding along with a number of Tubificids one or two white worms, one of which is new to Great Britain. I have therefore to place on record Fridericia striata (Levinsen). The spot where the worm was found is connected with a mill, and more than one curious find has been made in the same locality in days gone by. This remark is made lest it should be supposed that a worm hitherto known only in Denmark and Germany would be unlikely to appear in Great Britain. Ude has indeed given it, since Mr. Beddard's monograph was published, as a native of Monte Video, whence it was brought by Dr. Michaelsen; so that there is no reason why it should not be found with us. It has from six to eight setæ in a bundle, but the peculiarity which struck me as most characteristic was the gizzard-like enlargement of the intestine in segment ix. My specimen has forty-five segments, the first five or six of which are striated, or marked by some irregular bands or vacuoles, usually three in each segment.

Since I reported the destructive Enchytræus parvulus, Friend, as an aster pest last year, I have found it by the score along with another species of Enchytræus and the pretty Julus pulchellus in my own garden, where between them they have almost entirely destroyed a row of celery originally containing about one hundred sticks. It is evident that there is still room for a good deal of research among our micro-annelid fauna.