CHIEFLY OF THE UNITED STATES. 155 



The following species, heretofore described, were part of the envoi made by Dr. 

 Trask : 



Margaritana margaritifera. Lea. 

 Alas.falcata, Gould. 

 Alas. Yiibaeiisis, Trask, from Klamath and Yuba Rivers. 



I received specimens of this shell from Prof Nuttall in 1837, brought by him from 

 Columbia River. I thought then, and I still think that there were not characters 

 sufficiently distinct in them to form a new species. The observations published at 

 the time (Trans. Am. Phil. Soc. vol. vi. p. 97) are still in accordance with my 

 opinions after having had many specimens from various localities under examination. 

 The purple in the nacre is stronger than any I have seen from other localities, but 

 this with the other differences would not I think warrant its being considered more 

 than a mere variety of M. margaritifera. 



Anodonta Wahlaraatensis, Lea, Tr. Am. Ph. Soc, vol. vi. p. 78. = A. triangulata, 

 Trask, A. rotundovata, Trask. 



From Sacramento River. 

 Anodonta angulata, Lea, Tr. Am. Ph. Soc, vol. vi. p. 97. =^ A. feminalis, Gould, A. 

 Randalli, Trask. 



From Upper San Joaquin. 

 Helix Oregonensis, Lea, Tr. Am. Ph. Soc, vol. vi. p. 100. 



Point Cypress, Monterey C. ■-nty. 

 Helix Nickliniana, Lea, Tr. Am. Ph. Soc, vol. vi. p. 100. 



Tomales Bay and Deadmau's Island. 

 Helix Californiensis, Lea, Tr. Am. Ph. Soc, vol. vi. p. 99. 



Point Cypress, Monterey County. 

 Lymnaea exigua, Lea, Tr. Am. Ph. Soc, vol. 9, " Obs." vol. 3. 



San Antonio, Arroya. 

 Lymnaea pallida, Adams, Jour. Boston Nat. Hist. Soc, vol. 3 . 



San Antonio, Arroya. 

 Physa heterostropha, Say, Nicholson's Ency., Am. Edition. 



Los Angelos. 

 Melania occata, Hinds, Voyage of the Sulphur, pi. 15, fig. 5. 



Sacramento River. 

 Melania seminalis (Paludina Hinds,) Voyage of the Sulphur, pi. 16, fig. 22. 



Sacramento River. 

 Planorbis trivolvis. Say, Nicholson's Ency., Am. Edition. 



Kern Lake. Slightly varies from the Michigan specimens. 

 Planorbis ammon, Gould, Proc Bost. Soc. Nat. Hist., vol. v. p. 129. 



Lagoons Sacramento Valley. 



