FAUNA CANADENSIS. 493 



animal life consisted entirely of many minute Annelides. Close in- 

 shore, the bottom consisted of shingle derived from the shales and 

 grits of the Hudson River group. 



Lastly, an examination was made, partly with the dredge and 

 partly by means of a hand-net, of the shallow water in the immediate 

 neighborhood of the "Island," and of the extensive ponds which com- 

 municate with the lake. The bottom here consisted, for the most 

 part, of a black mud, composed almost entirely of decayed vegetable 

 matter, and supporting a luxuriant growth of Vallisneria, Ponte- 

 deria, Char a, Anacharis, JS^ymphcea and Ntiphar. Animal life was, 

 naturally, extremely abundant, comprising numerous examples of 

 Lwincea, Physa, Planorhis, Pcdudina, Gyclas, Pisidium and Anodon, 

 along with two species of Gammar%is and many small Ostracode 

 Crustaceans, a few small leeches (Cl&psine), veiy many large scarlet 

 water-mites {Limnocliares), numerous aquatic insects [Nejoa, Gyrinus, 

 DytisGus, and larvse of Ghironomus, LiheClida, kc), and a large niim- 

 ber of young fishes (Pimelodus, Perca, &c.). Numerous Terrapins 

 were also observed, and a single specimen of Menohranchus, but the 

 latter unfortunately was not secured. 



In the following are given the chief characters of the animals 

 obtained in these dredgings. The microscopic species have, however, 

 been, in the meanwhile, omitted from the list. Owing, also, to the 

 impossibility of obtaining here the necessary works of reference, it 

 has not been found feasible in all cases to determine the species, or 

 in some cases even the genus, of some of the specimens. 



ANNELIDA. 



Of all the forms obtained in the dredgings none are of greater 

 interest than the Annelides. Both the Hirudinea and Oligochceta 

 are well rei^resented, some of the former exhibiting points of special 

 interest. Some of the Oligochfetous Annelides, also, have an 

 extremely wide range, extending to nearly the greatest depths 

 examined, and being rarely absent when the bottom is of a muddy 

 nature. They did not appear to exist, however, in deptlis beyond 

 twenty fathoms, though small Crustaceans were found at far gi'eater 

 depths than this. 



The total number of Annelides which have been made out is seven, 

 three species of Naididce and four species of Leeches. Of the former 

 one species is new, and of the latter no less than three species appear 



