THE HAMILTON ASSOCIATION. IIQ 



Sph^rium STRAMINEUM. 



Ancaster Creek, near marsh ; very plentiful. 



Sph^rium occiuentale, Prime. 



Taken in Canal near Dundas ; also in streams running through 

 open woods, among and under the dead leaves. 



GENUS PISIDIUM, PF'r. 



PisiDiUM abditum, Prime. 



Hamilton Bay and Dundas Marsh. 



PiiTDiUM coMPRESSUM, Prime. 



Dundas Marsh ; only two or three specimens taken. 



A THIRD SPECIES, as yet unnamed. 



The Sphceria and Pisidia live in the mud in ditches, streams, 

 etc. ; the latter from their small size are seldom noticed, or 

 are mistaken for young shells. 



FAMILY UNIONID^E. 

 SUB-GENUS UNIO, RETZIUS. 



Unio alatus, Say. 



Occurs in the Bay ; a few large shells have been picked up on 

 the shore between Willow and Carroll's Points. 



Unio gracilis, Barnes. 



One very large specimen found on Carroll's Point. 



Unio gibbosus, Parties, 



Have seen some valves supposed to have been picked up at the 

 Beach; is likely to occur there. 



Unio complanatus, Sol. 



Very common ; Hamilton Bay. 



Unio nasutus, Say. 



Occurs at Carroll's Pciint, and at other places around the Bay. 



Unio luteolus, Lam. 



Very common around Hamilton Bay ; very variable in size, 

 colour and markings ; some shells are very handsome. 



Unio subovatus. Lea. 



A few dead shells have been taken near Carroll's Point belong- 

 ing most likely to this species. 



