1863.] DR. p. V. CARPENTER ON THE SHELLS OF PANAMA. 351 



219. Chemnitsia aculeus, M. 521. 



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

 sallida, 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 

 round the base *. 



221. Chemnitsia 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 Chemnitsia unclata, 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. Chemnitsia clathratula, -part. = Chri/sallida 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 ChrysaUida 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 four in the Chrysallida ; 

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

 latter are well rounded. 



223. Chemnitsia 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. 510; one of Ghrys. 

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

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



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

 only seen in some of the whorls. 



225. Chemnitsia major belongs to the section Bunkeria. I counted 

 eighteen (not twenty-four) ribs. 



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

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



227. Chemnitsia j^anamensis, 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 work ; nor vras the instrument a good one when ob- 

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

 nomy and Matliematics, 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 Ufe is marvellous. Had that life been spared to 

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



