1863.] DR. p. p. CARPENTER ON THE SHELLS OF PANAMA. 361 



some are undoubtedly C. nivea ; others truly C. unguiformis ; and 

 others probably C. nivea, but with the riblets worn away by the 

 crabs. 



351. Crepidula nivea, M. 341. The specimens are small and 

 poor ; mostly rough, of the variety striolata passing into lessonii. 

 Wherever the apex is perfect, it presents the characteristic riblets, 

 but is generally white, not brown as in most of the finely grown 

 Mazatlan shells. 



352. Crepidula osculans. This is a perfect and extremely beau- 

 tiful specimen of Scutellina navicelloides, M. 269. The Professor 

 did not observe the non- spiral patelloid apex, and regarded the 

 " navicelloid " columella as an extremely narrow deck. To the diag- 

 nosis in the Maz. Cat. may now be added " apice obtuso, sublavi ; 

 vertice haud spirali, vix conspicuo," 



353. Crepidula rostrafa=C. adunca, M. 338, ?non Shy. The 

 examination of a large series of specimens from the temperate fauna 

 has led me unexpectedly to confirm Mr. Reeve's opinion that they 

 are distinct. The northern shell is C. adunca, Sby. {=.Garnotia 

 [Gray] solida, Hds.= C'. rostriformis, Gld.) ; and the tropical shell 

 must take the prior name, C. uncata, Mke. (=C rostrata, C. B. Ad., 

 E,ve. = C adunca, Maz. Cat., non Sby.). 



354. Fissurella a:qualis=^Fissurellidcea cb. 



355. Fissurella alta=Glyphis alta, M. 280. 



356. Fissurella macrotretna. Stet. 



35/. Fissurella microtrema. These are dead specimens, of which 

 some are F. rugosa, var., M. 273. 



358. Fissurella mus=-Glyphis ineequalis, var., M. 279. These 

 shells are intermediate between the typical form and pica. 



359, 360. Stent. 



361. Fissurella virescens. It is doubtful whether any of the spe- 

 cimens are of the true virescens, M. 271, as they run into nigro- 

 punctata by insensible gradations. Perhaps both species may prove 

 identical. 



362. Siphonaria characteristica=S. gigas, var. 



363. 364, 365. Stent. 



366. Siphonaria 1 pica. These are young dead limpets (not 

 Siphonarice). 



367. Lottia 1 patina, C. B. Ad. (non Esch.). These shells differ 

 from Acmcea mesoleuca, M. 263, in being black instead of green, and 

 are prettily striped. 



368. 369, 370. Lottia, sp. ind. There maybe two or even more 

 species of Acmcea, but it is not impossible that there is only one 

 among the Professor's Lottice, some of the specimens being the 

 young oilPatella, no. 371. 



