178 UNITED STATES GEOLOGICAL SURVEY OF THE TERRITORIES. 



Pitar, Roemer (1857), Kritiscbe Uuters. der Arten des Moll., 15; ami (1862), Malakoz. Bliitt., 



IX, 58.* 

 Caryatis, Roemer (1807), Monogr. der Moll., 79 (as a subgeuus of Venus). — Stoliczka (1870), 



l'al.iTint. rndioa, III, l. r >7 (as a subgenus of Cytherea; not Caryatis, Hubn. 1816, genus 



Lepidoptera). 

 ? Dosiniopsis, Conrad (1864), Proceed. Acad. Nat. Sci. Pbilad., 213 (subgenus). 

 Amianiis, Carpenter (1865), Ann. and Mag. N. II , XV, 178 (as a subgenus of Callisla). 

 Aphrodina, Conrad (1868), Am. Jour. Concb., IV, 246; and (1S7I ! ) in Appendix Kerr's N. Car 



Geol. Report, 7. 



Etym. — KaWiarii, most beautiful. 

 Type. — Vhiiis ehione, Linn. 



Shell varying from transversely-ovate to elongate-ovate, subtrigonal, or 

 subcircular, more or less convex, and inequilateral, with free margins closed, 

 smooth, and often obtuse; hinge with three diverging cardinal teeth in each 

 valve, the anterior two of left valve united at the apex, and one approximate 

 anterior lateral under the lunule ; rarely provided with a remote rudimentary 

 posterior lateral tooth in one or both valves; pallial sinus generally deep, 

 triangular, linguiform, or often abruptly pointed at the end; surface con- 

 centrically sulfated, striated, lamellose, or smooth ; sometimes with more or 

 less angular posterior umbonal ridges that rarely bear spines. 



This genus, as here defined, is intended to include the following 

 sections : 



1. callista, Poli (typical, — Chione, Gray; not of Miihlfeldt). 



Shell transversely ovate or subtrigonal, usually moderately com- 

 pressed, with surface smooth or concentrically sulcate; sublunular 

 tooth generally close to the cardinal teeth, smooth, more or less com- 

 pressed, but not much elongated; pallial sinus deep, and often abruptly 

 pointed at the end. — (Type as already stated.) 



2. dione, Gray. 



Shell very nearly typical in form and dentition, but with surface 

 always distinctly sulcate or lamellose concentrically, with posterior 

 umbonal slopes more or less prominent or subangular, and sometimes 

 bearing a row of spines ; pallial sinus deep, and generally obtuse at 

 the end. — Venus Dione, Linn. 



* I think tbe rule of priority of date will compel us to adopt Roemer's first name Pitar for this 

 group, notwithstanding its barbarous origin. He first used it in 1857, giving a diagnosis, and citing 

 Venus titmens, Gmelin, as tbe typical species; and, if I am correctly informed, it was not until tbe pub- 

 lication of bis Monograph, in 1867, ten years later, that be changed the name from Pitar to Caryatis, 

 citing the same species as tbe type. This change, it seems to nie, be bad no right or authority to make; 

 for, when an author once regularly publishes a new genus or subgenus, he has no further control over it, 

 and can only change or modify the name where the circumstances are such that any one else could do so. 

 Descriptive names are, of course, preferable in first selecting a name for a new genus; but it will hardly 

 be maintained that any one would have the right to change all of the regularly-published barbarous and 

 nonsense nanus now curroul in natural history. 



