Annelides. 1039 



was omitted by accident, as the latter species is mentioned incidentally, when speaking 

 of Modiolus minutus. The Cyclas above named I found in a small pool close to the 

 church of St. Erme, near Truro. They were of larger size and more oblong in shape 

 than those I obtained near Cambridge, nor do they agree so well with the beautiful 

 figure of the shell in Turton's * British Bivalves.' The pool had dried up a few days 

 before, and some dead shells on the surface of the mud betrayed the survivors. When 

 I first put them into water they were very lively, and immediately began to climb the 

 sides of the glass. One of them also commenced crawling on the under surface of the 

 water. Its foot was now spread out very widely, after the fashion of the Limnaeadae ; 

 and, while preparing for its exploit, it was apparently kept near the surface by a minute 

 thread fastened to the sides of the glass. When it had left the side, its foot appeared 

 to be depressed in the middle, so as to act as a kind of boat. I shook the tumbler, so 

 as to fill the little vessel with water, but to my surprize it sunk, not suddenly, but gra- 

 dually, as if it were lowering itself by a thread attached to the surface of the water. 

 Under ordinary circumstances they always sunk directly, even when they had air with- 

 in the shell, so that their specific gravity must be greater than that of the water. They 

 also appeared to give out a quantity of glutinous matter wherever they went ; so much 

 so, that in about half an hour seven or eight were entangled and tied together by each 

 others' trailing threads. After the first three hours I did not notice so much of this 

 glutinous matter. Perhaps, if I might be so bold as to suggest it, a part of the ani- 

 mal's economy induces and assists them to secrete this matter in greater quantities 

 than usual, when deprived of water for any considerable length of time, as these had 

 been. And it appears to me quite possible that this may conduce to the animal's pre- 

 servation under circumstances so untoward. This may appear to many a much less 

 curious circumstance than, I confess, it appears to me. — Robt. L. King ; Grammar 

 School, Truro, June 9, 1845. 



Cocoon of the Horse-leech. It appears that the body which Mr. Bowerbank, in a 

 paper read before the Microscopical Society, described as a new genus of fresh-water 

 sponge, under the name of Stomatispongia pulchella (Zool. 1003), turns out to be 

 the cocoon of the horse-leech (Hirudo sanguisuga). Mr. Bowerbank's attention hav- 

 ing been called to the mistake by Professor Henslow, he gives the following amended 

 description in the June number of the 'Annals and Magazine of Natural History.' — 

 " It is of an oval form, and rarely exceeds half an inch in length from one extremity 

 of the fibre to the other, and the central case is about four lines long. The fibres are 

 of a greenish amber colour, the case partaking of the same hue, but much deepened 

 by its greater degree of density. When carefully denuded of the surrounding fibre, 

 the case is found to be divided into numerous nearly equal-sized polygonal areas, which 

 are most frequently five- or six-sided. These are produced by a raised network of fi- 

 brous structure, partly imbedded in the surface. From the angles of these reticula- 

 tions the surrounding open fibrous structure springs, which preserves the same form of 

 reticulation as that of the parent surface. The case has frequently a deep sinus which 

 extends entirely across it, causing it to assume very much the same form as a short, 

 swollen grain of wheat ; and under these circumstances the mammae are found oppos- 

 ed to each other iu the direction of, what is then, the short axis of the case, and are 

 situated just without the outer edge of the sinus. When there is no depression of this 



