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 Binney, Tryon. 
Fluminicola fusca, Hald. (Leptovis f.). Shores of Lake Utah, Capt. Burton. 
117. Of the West Coast species of Melaniadze 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 Melaniade 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- 
laniadze and the Unionide, 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 
Rafinesque and other similarly inaccurate authors, which would be considered 
by most English naturalists as not warranted by 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 Melania, Lithasia, Gyrotoma, Leptoais, and Jo, Mr. Binney 
assigns the following eleven to the West Coast. None of them are accredited 
to the eastern division. 
43, Melania bulbosa, G1d. | 242, Melania Shastaénsis, Lea. Shasta 
104, Melania exigua, Conv. and Scott Rivers. 
166. Melania Menkeana, Lea. 243. Melania silicula, Gld. [=M. plici- 
174. Melania Newberryt, Lea. era, small var., teste Lea. | 
177. Melania nigrina, Lea. Clear Creek, | 296. Melania Wahlamatensis, Lea. 
Shasta Co. 297. Melania Warderiana, Lea. 
211. Melania plicifera, Lea. 360. Melania fusca, Hald. 
118. Dr. Lea’s Check-List of the Unionide (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. xxxviii., 
July 1864, pp. 41-53. It appears that the sexual system is quite distinct from that of the 
ordinary Ctenobranchiate Gasteropods, and approaches the Cyclobranchiates. 
