NORTH AMERICAN CONCHOLOGY. 



429 



Page. 



Anodonta Ferussaciana Lea. 

 38 subcylindrica Lea. 

 edentula Lea. 



Unio areolutus Sw. 



Anodonta undulata Say. 

 Unio Pennsylvanica Lara. 

 cylindrica Lea ? 

 Benedictensis Lea. 

 imbecillis Say. 



Parker. — Description of a new species of Helix: by Samuel 

 J. Parker. In Proc. American Ass. Adv. Science. Vol. IV, 

 p. 348. 1841. And 



Ag'assaz. — Criticism on the same: by Louis Agassiz. 



[I introduce these references on account of their being included in Mr. 

 Tryon's Catalogue of American Conchological Writings. No specific name 

 or description was given of the supposed new species. — W. G. B.] 



Hillings. — Notes on the Natural History of the Mountain of 

 Montreal. (From the Canadian Naturalist and Geologist, vol. 

 ii, No. 2. May, 1857, p. 92.) Terrestrial Mollusca, p. 97 : by 

 E. B. [E. Billings.] 



Page Fig. 



93 2, 3 Helix albolabris Say. 



99 4, 5 alternata Say. 



100 6 monodon Rackett. 



AllOBBVinoiSS. — Description of some of the Fresh-water Gas- 

 teropoda inhabiting the Lakes and Rivers of Canada. (From 

 the same as the last article, vol. ii, No. 3. July, 1857.) 



Page. Fig. 



196 1,2 



197 (fig.) 



197 (fig.) 



198 (fig.) 



198 (fig.) 



199 (fig.) 



201 (fig.) 



202 (fig.) 



203 (fig.) 



204 (fig.) 



204 (fig.) 



205 (fig.) 

 20G (fig.) 



LimnaeastagnalisZ^n?*. 



columella Say. 

 var. cha/ybea. 



macrostoma Say. 



desidiosa Say. 



elodes Say. 



catascopium Say. 

 Planorbis trivolvis S. 



lentus Say. 



bicarinatus Rackett. 



campanulatus Say. 



armigerus Say. 



hirsutus Gould. 



Planorbis deflectusSay. 

 exacutus Say. 

 parvus Say. 

 dilatatus. 

 Pkysa heterostropha 

 ancillaria Say. [Say. 

 elongata Say. 

 Ancylus rivularis-Sa?/. 



fuSCUS Ada /us. 



Valvata tricarinata S. 



pupoidea Gould. 

 Amnicola porata Say. 



