5 GEORGE V. SESSIONAL PAPER No. 39b A. 1915 



VII. 

 NOTES ON THE HIRUDINEA OF GEORGIAN BAY. 

 By Miss C. G. S. Ryerson, B.A., University of Toronto. 



Some time ago Dr. E. M. Walker placed in my hands, for the purpose of iden- 

 tification and morphological study, the entire collection of Hirudinea belonging 

 to the Georgian Bay Biological Station. This collection contained numerous 

 specimens obtained in different seasons and particularly the special collection 

 made by Mr. R. C. Coatsworth in 1910. This collection was accompanied by 

 extensive field notes which were kindly placed at my disposal by Mr. Coatsworth, 

 and which have been freely used. Useful information has also been supplied 

 by Mr. A. D. Robertson. In several cases it has been difficult to make satisfactory 

 determination on account of lack of information on anatomical features, a study 

 of which is now in progress. 



Hitherto, collections of leeches have been made chiefly in the lakes and rivers 

 of the United States and little work has been done in Canadian waters. Bristol 

 (1899) in his paper on the Metamerism of Nephelis, mentions having received 

 several specimens from Toronto. Verrill (1872) found Ichthyobdella punctata in 

 Lake Superior. Nicholson (1872) in his "Contributions to Fauna Canadensis" 

 describes four species from Lake Ontario. Moore (1905) in his paper on "Hirudinea 

 and Oligochseta of the Great Lakes," describes species which, except for two 

 parasitic forms are common around Toronto. 



There appear to be four families represented in the Georgian Bay region, 

 namely, the Glossiphonidce, Hirudinidoe, Erpobdellidce, and IchthyohdellidcB. 

 Judging from the field notes, there is a great uniformity in the environmental 

 conditions of the various species. Whether free-swimming forms such as the 

 Hirudinidce and Erpohdellidce or less active creeping forms such as the Glossi- 

 phonidce, leeches, as a rule, choose sheltered places where their movements will 

 not be hampered by the motion of the water. Further in such places are found 

 snails, oligochsetes and other invertebrates which form the food of the majority 

 of species. Semi-permanent parasites such as Placobdella parasitica or the 

 IchthyobdellidoB accommodate themselves to the environment of the host, but 

 during the breeding season retire to the shelter of plants or stones. 



The following is a list of the species herein described: 



I. Family Glossiphonid^. 



A. Genus Glossiphonia, Johnston. 



1. G. stagnalis, Linn. 



2. G. fusca, Castle. 



3. G. nepheloidea, Graf. 



4. G. heteroclita, Linn. 



5. G. complanata, Linn. 

 396— 11 J u 



