ON MOLLUSCA OF THE WEST COAST OF NORTH AMERICA. 



677 



ecarinate forms of V. tricarinata, Say," to which the Clear Lake specimens 



bear but slight resemblance.] 

 Pomatiopsis Itinneyi, Tryon. 

 Fluminicola fusca, Hald. (Leptoxisf.). Shores of Lake Utah, Capt. Burton. 



117. Of the West Coast species of Melaniadse we are unable to offer any 

 list embracing the synonymy, as the materials are at present in the hands of 

 Mr. Tryon for elimination, and his labours are not yet sufficiently advanced 

 to furnish a report. His Manual of the North American Melaniadas will be 

 published by the Smithsonian Institution. The animals of many species have 

 already been dissected by Dr. Stimpson*. It is unfortunate that in the two 

 most important branches of North American freshwater molluscs, the Me- 

 laniadae and the Unionidae, there exists a radical difference of opinion between 

 the leading writers, which has sometimes assumed the appearance of per- 

 sonal animosity. Malacologists east of the Atlantic, unwilling to become 

 partisans when the leading nomenclators of the rival schools are equally 

 honoured, have to a great extent declined to pay attention to the unexhausted 

 riches of the American waters, regarding any settlement of the disputed 

 points as hopeless. Dr. Isaac Lea, who has spared no expense in illustrating 

 his publications of the results of a life-long study, follows the restrictions 

 on the priority-rule allowed by the British Association Committee. Other 

 writers, however, claim a certainty in identifying the supposed species of 

 Bafinesque and other similarly inaccurate authors, which would be considered 

 by most English naturalists as not warranted b_y the few loose words of de- 

 scription given. It would be well if the student were permitted to start from 

 the first carefully ascertained landmark, rather than from the defaced tracks 

 of the first hunter. 



In the Check-List of North-American Fluviatile Gasteropods, published by 

 the Smithsonian Institution. June 1860, which contains the names of 405 

 (supposed) species of Melanin, Lithasia, Gfyrotoma,Leptoxis, and lo, Mr.Binney 

 assigns the following eleven to the West Coast. None of them are accredited 

 to the eastern division. 



43. Melania bulbosa, Old. 



104. Melania exigua, Conr. 



166. Melania Menkeana, Lea. 



174. Melania Newberryi, Lea. 



177. Melania nigrina, Lea. Clear Creek, 



Shasta Co. 



211. Melania plicifera, Lea. 



242. Melania Shastaensis, Lea. Shasta 



and Scott Rivers. 



243. Melania silicula, Gld. [=M.plici- 



fera, small var., teste Lea.] 



296. Melania Wahlamatensis, Lea. 



297. Melania Warderiana, Lea. 

 360. Melania fusca, Hald. 



118. Dr. Lea's Check-List of the Unionidae (June 1860), after eliminating 

 synonyms, assigns to America, north of Mexico, no fewer than 552 species 

 of Unio, Margaritana, and Anodonta. The type-specimens of the species 

 described by Dr. Gould from the United States Exploring Expedition were 

 submitted to Dr. Lea's inspection, and confirmed his previous opinion that 

 they were varieties of those before known. The U. famelicus, Gld., he pro- 

 nounced to be a South- American shell ; but it appears, without note, in the 

 Check List, no. 133, probably by oversight. The only widely diffused species 

 is the long-famed " pearl-mussel" of the Conway and other British streams. 

 The following seven are accredited to the Pacific coast : 



* See his very interesting and important paper " On the structural Characters of the so- 

 called Melanians of North America," in the 'American Journal of Science,' vol. xxxvii?., 

 July 1864, pp. 41-53. It appears that the sexual system is quite distinct from that of the 

 ordinary Ctenobranchiate Gasteropods, and approaches the Cyclobran dilates. 



163 



