Dr. H. A. Nicholson on Dredgings in Lahe Ontario. 281 



green intestinal tract. The antennas and antennules are about 

 lialf the length of the body, and nearly equal. Numerous 

 examples of this pretty little species occurred amongst Charas 

 and other water-weedsj in from 1 to 3 fathoms. 



8. GammaruSj sp. 



A minute form, not uncommon in shallow water in the 

 ponds at the " island." 



9. Crangonyx (?), sp. 



A small Amphipod, as yet unexamined, which may perhaps 

 belong to this genus. 



Common in from 10 to 15 fathoms, amongst branches of 

 Clado^ho7-ay upon a muddy bottom. 



10. Cyp'is (?), sp. 



A small Ostracode Crustacean, as yet undetermined, which 

 occurred plentifully, along with the preceding, amongst Glado- 

 'pliora at depths of from 10 to 15 fathoms. 



11. Pontoporeia affinis (Lindstrom). 



Small Amphipods, varying in length from y\, up to ^ 

 inch, of nearly uniform flesh-colour. They aire referable to 

 the genus Pontoporeia ; and though they have not yet been 

 satisfactorily examined, I have little doubt as to their being- 

 identical with the Pontoporeia affinis of the Swedish lakes and 

 of Lake Superior. 



They occur in great plenty in from 30 to 45 fathoms ; but 

 none were found in depths less than this, though they are 

 found in Lake Superior in all dredgings, from the shallowest 

 to the deepest. They were uniformly found inhabiting a 

 muddy bottom ; and they died very shortly after they were 

 brought to the surface. 



Arachnida. 



12. Limnochai-eSj sp. 



A fine species of this genus was extremely abundant in 

 shallow water and in the ponds at the " island." 



13. Hydrachnaj sp. 



A small water-mite of this genus occurred abundantly in 

 Toronto Bay in from 1 to 2 fathoms. 



Insecta. 



14. Chironomus or Corethra^ gp. 

 The larvffi of a species of Dipteron belonging to one of the 

 Ann, & Mag. N, Hist, Ser, 4. Vol x. 21 



