MUSEUM OF COMPARATIVE ZOOLOGY. 3G3 



where a single rounded riblet or carina bounds a somewhat concave lunate 

 space outside of the ])oli.shed columella; outer lip thin, sliarp, a moderate 

 callus on tlie body; pillar thick, polished; operculum translucent yellowish, 

 of about live turns ; aperture rounded, with a slight angle behind. Diam. of 

 shell, 4.0; of aperture, 2.0; height of shell, 3.0 mm. 



Habitat. Station 215, oil' St. Lucia, in 22G fms., coarse sand, bottom tem- 

 perature 51°.0. 



This little shell will not fit into any of the groups defined in the text-books, 

 resembling more than any other group the Ilotellidce, from which it differs in 

 wanting the sutural fasciole, the nacreous layer, and the basal callus, as well 

 as in possessing an epidermis. It is remarkably solid for its size, and of a 

 peculiar opaque whiteness, like Mamma among the Naticidce. It is named in 

 honor of the respected Dr. Dillwyn, whose " Catalogue " is one of the most 

 careful and judicious works of the kind among the many which were published 

 between the tenth edition of the " Systema Naturse" and the epoch-making 

 '' Histoire des Animaux sans Vertebres" of Lamarck. 



Genus CALLI0ST03IA Swainson. 



Calliostoma Swalnson, Malacology, pp. 218, 351, 1840. 

 Ziziphinus Gray, Synops. Brit. Mus., 1840. (No description.) 



There is no doubt that Swainson's name was defined in a proper manner, 

 and published, before the name published by Gray and ascribed to an old 

 manuscript of Leach. As the duplication of such a word as Ziziphinus has a 

 particularly obnoxious sound, and the practice is condemned by all nomen- 

 clators and all rules, there would seem to be no reason except the natural 

 perversity of human nature wby any one who knows the facts should adhere 

 to Gray's name in preference to the other. The type is Trochis conulus L. 

 The nucleus appeases to be either dextral or sinistral indifferently. 



Section CALLIOSTOMA s. s. 

 Not umbilicated. 



Calliostoma euglyptum A. Adams. 



Zizyphinus euglyptus A. Adams, P. Z. S. 1854, p. 38. Reeve, Mon. Zizyph., pi. iii. 

 fig. 17, 1863. 



Habitat. Off the eastern coast of America, in 15-50 fms., from North 

 Carolina to Florida, Texas, and Vera Cruz, Mexico. Fossil in Florida Pliocene. 



This fine species varies in color from dark rose to yellowish white, some- 

 times unicolor, sometimes variegated with whitish clouds radiating from the 

 invariably purplish apex. It was referred by Reeve to Tasmania, in error. 

 It is the commoner imperforate species of Florida, often collected by tourists. 



