Dr. H. A. Nicholson on Dredgings in Lake Ontario. 283 



23. Physa heterosfropha^ Say. 

 Veiy common in shallow water at the "island." 



24. PJiysa^ sp. 

 A smaller form, rare in from 1 to 3 fathoms. 



25. Melama, sp. 



A form nearly allied to, if not identical with, the M. depygis 

 of Say {=M. niagarensis^ Lea?). 



Common in from 2 to 3 fathoms in Toronto Bay. 



26. Cyclas similis, Say. 

 Common in from 1 to 3 fathoms. 



27. Pisidium abditum^ Haldeman. 



Common in from 2 to 5 fathoms. 



28. Unio crassidens, Lam. 

 Common, lioth in the living and dead state, in from 1 to 3 

 fathoms in Toronto Bay. 



29. Um'o, sp. 



A large ventricose form, common at the same depths and lU 

 the same locality as the preceding. 



Vertebrata. 



30. Pimelodus catus (=-f*. atrarius). 



The young of this species, not more than 1 inch to li inch 

 in length, occurred abundantly in the pools in the vicinity of 

 the "island." 



31. Pomotis vulgaris. 



The young of the sunfish or northern Pomotis of Richardson 

 occurred not uncommonly in shallow water at the " island." 



32. Perca flavescens^ Cuv. 



The American yellow perch. 

 Common throughout Toronto Bay. 



33. Leicciscus. 

 Two individuals of a small species of this genus were brought 

 up by the dredge in Toronto Bay from a depth of about 2 

 fathoms. 



General Observations. 

 In a mere preliminary report there are but a few general 

 considerations which require notice. Upon the whole the 



21* 



