34 [Senate 



Many varieties, I send, differing in form and color, and radiations; one 

 nearly black. The variety of names is obvious. Abounds in the Gene- 

 see, especially above the falls at Rochester ; the longest being six inches 

 by three. 



S Unio pressus, Lea. 



U. coMPREssus. Dekay's New-York Fauna, Part V, pa. 191, pi. 21, 



f. 245. 



U. id Conrad. Adams. 



Mr. Conrad's name had already been applid to a fossil Unio, and hence 

 the new specific name by Mr. Lea. From the Genesee river; the Erie 

 canal; and one from Ohio. 



9 Unio complanattjs, Lea. Dekay's New- York Fauna, Part V, pa. 188, 



pi. 22, f. 246. 



U. id Grould. Adams. 



U. puRPUREUs, Say. Barnes. €onrad. 



Mjta complanata, Solander. 



Mya rigida. Wood. 



As this species is quite variable, I send a dozen or more varieties, 

 younger and older, longer and shorter, &c. The nacre varies from white 

 to light purple, deep reddish purple, and fine orange or reddish yellow. 



I give the height and the length and breadth of several from dififerent 

 localities, in inches. 



From the Genesee river ; some shade of purple. 



3.75 & 2.25; 4.25 & 2.25; 4.50 & 2.33; 433 & 2.25; 2.40 & 1.33; 1.10 & 

 0.50; 3.75 & 2.40. 



From below the falls; white., 3.35 & 2.10. Purple. 4.25 & 2.25. 



From the Genesee river, both above and below tho falls ; fine yellow. 

 4.20 & 2.50. 



From the Erie canal. 3.70 & 2.25. 



From the Delaware river. 4.10 & 2.20 ; 3.10 & 2.20. 



From New-Jersey. 4.00 & 2.30. 



This species has a strong shell. 



The variety in the form has originated many names or species. 



It is stated by our conchologists, that Lamarck made six or eight 

 species from these varieties. 



a Unio purpurascens, Lam. Stated by him to be from the rivers of 



this State. Corresponds to the promi- 

 nent form. 



