ER. P. P. CARPENTER ON THK SHELLS OF PANAMA. 13 



219. Chemmtzla aculeus, M. 521. 



220. Cliemiiitzia acuminata is a true Chemnitzia, and not a Chnj- 

 sallida, as siii)posed in the Br. Assoc. Report, p. 334. The name 

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

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

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

 on the ])eriphery of the last whorl," become gradually evanescent 

 rounJ 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 diti'erence is that the ribs evanesce more suddenly 

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

 to age. 



222. Chemnitzia clathratida, Tpart. = C/iiysallida clathratu/a, M. 

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

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

 ChrysaUida coinminiis, one (almost certainly) of Chi'ysallida effusa, 

 M. 510, and one oi 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 ChrysaUida; 

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

 latter are well rounded. 



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

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

 tains also one specimen of ChrysaUida effasa, JM. 510; one of Chrys. 

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

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



224. Chemnitzia graciHor. 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. 



22fi. Chemnitzia marginata is a good species of ChrysaUida; 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 tlie work ; nor was the instrument a good one when ob- 

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

 uomy a'ld Mathematics, as well as of Natural History, and Jiis duties as State 

 Geologist of V'erraont, 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 uecc.-isity loi uiis friendly criticism would not hu\e ariaeii. 



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