DK. P. P. CARPENTER ON THE SHELLS OF PANAMA. 13 



219. Chemnitzia aculeus, AI. .521, 



220. Chemnitzia acuminata is a true Chemnitzia, and not a Chry- 

 snUida, as supposed in the Br. Assoc. Report, p. 334. The name 

 misleads, as it is a peculiarly broad species. The vertex consists' of 

 three Paludinoid whorls, of which the apex is visible, projecting a 

 little beyond the spire. The ribs, instead of " terminating abruptly 

 on the periphery of the last whorl," become gradually evanescent 

 lounJ the base*. 



221. Chemnitzia affinis. Comp. M. .523, which was identified 

 from Mr. Cuming's specimen. The diagnosis needs the following 

 corrections from the type. The "ribs terminate " not very " abruptly 

 at the periphery." Anteriorly very finely striated [not " smooth "]. 

 " Last whorl " not " angular at the periphery." Base prolonged. 

 It is probably the adult form of my Chemnitzia undata, M. 531, the 

 characteristic fine, waved, spiral striae having escaped the Professor's 

 notice. The only difference is that the ribs evanesce more suddenly 

 in the Panama than in the Mazatlan shell, which may be due simply 

 to age. 



222. Chemnitzia clathratula, ^9xt. = Ghrysallida clathratula, M. 

 .513, which was identified from the Cumingian specimen. The spe- 

 cimens preserved as types contain, along with this species, one of 

 Chrysallida communis, one (almost certainly) of Chrysallida effusa, 

 M. 510, and one of Dunkeria subangulata, M. 537. Some parts of 

 the description appear taken from the latter species : e. g. the " five 

 or six " spiral lines, of which there are only foui- in the Chrysallida ; 

 and the angle on the " upper part " of the whorls, which in the 

 latter are well rounded. 



223. Chemnitzia communis, M. 507. This is the type of the 

 genus Chrysallida: v. M. pp. 416, 420. Prof. Adams's tray con- 

 tains also one specimen of Chrysallida effusa, M. 5 1 ; one of Chrys. 

 telescopium, M. 508; one of Dunkeria subangulata, M. 537; and 

 one which may be a variety of the latter, or a distinct species. 



224. Chemnitzia gracilior. The " well-impressed spiral line " is 

 only seen in some of the whorls. 



225 Chemnitzia major belongs to the section Dunkeria. I counted 

 eighteen (not twenty-four) ribs. 



226. Chemnitzia marginata is a good species of Chrysallida ; but 

 I could not find the "spiral, compressed ridge." 



227 Chemnitzia panamensis, M. 518. I counted twenty-four 

 (not twenty-seven) ribs. The tray also contains one specimen of 



* As several errors are here pointed out in the diagnoses of small shells, it is 

 right to state that Prof. Adams had not the advantage of a microscope during a 

 considerable portion of the worlt ; nor was the instrument a good one when ob- 

 tained. Moreover the incessant demands on his attention as Professor of Astro- 

 nomy and Mathematics, as well as of Natural History, and his duties as State 

 Geologist of Vermont, did not leave him much time for original research. What 

 he accomplished during his short life is marvellous. Had that life been spared to 

 revise his works, the necessity for this friendly criticism would not have arisen, 



187 



