196 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 85 



Breathing device present — Continued. 



Breathing device not a slit but a puncture — Continued. 

 Shell not turbinate — Continued. 

 Shell not turreted. 

 Shell ovate. 



Unabilicus open. 



Last whorl solute Hendersonoma (p. 252) 



Last whorl not solute. 



Inner lip of outer peristome with a plication. Plicathyra (p. 263) 

 Inner lip of outer peristome without a 



plication Chondrothyra (p. 252) 



Umbilicus closed. 



Inner Hp of outer peristome cut Chondrothyretes (p. 269) 



Inner lip of outer peristome not cut but v.ith 



a deep pit Foveothyra (p. 265) 



Shell not ovate. 

 Shell subglobose. 



Umbilicus open Plicathyrella (p. 306) 



Umbilicus closed Chondrothyrella (p. 306) 



Genus CHONDROPOMETES Henderson and Bartsch 



1920. CJwndropoiuctes Hendkrsox and Bartsch, I'roc. U. S. Nat. Mus., vol. 58, 

 p. 60. 



Shell of turbinate form, openly lunbilicatecl, marked by axial and 

 spiral threads. Lip simple or double. Breathing pore present or 

 absent. Opercnlnm subcircular, multispiral with the inner part of 

 the whorls covered with a heavy calcareous calliislike deposit. 



Type: Chondropometes {Chondropometes) vign/jJense (Wright) 

 Pfeiffer. 



In 1920 - Henderson and Bartsch created the subgenus Chondropo- 

 metes, making it a subdivision of Chondropoma. They likewise 

 founded the subgenus C hondrofhyroma,- placing this under their 

 genus Chondrothyra. The finding of specimens of Chondropometes 

 {Ghondrothyroma) scopulorum perplexum and C. (C.) magnum 

 magnum without breathing pore, leads us to make the following re- 

 alignment, Avhich we believe to be phylogenetically and zoogeographi- 

 cally more sound. 



KEY TO THE SUBGENERA OF GENUS CHONDROPOMETES 



Breathing pore pre.seut . Ghondrothyroma (p. 212) 



Breathing pore absent Chondropometes (p. 196) 



Subgenus Chondropometes Henderson and Bartsch 



1920. Chondropometes HE^'DKRS0N and Bartsch, Proc. U. S. Nat. Mus., vol. 58, 

 p. 60. 



Chondropometes without breathing pore. 



Type: Chondrojyometes {Chondropometes) vignaJense ("Wright) 

 Pfeiffer. 



- Proc. U. S. Nat. Mus., vol. 58, p. 63, 1920. 



