270 CASSIS. 



nodulous whorls, and prominent, recurved siphonal canal ; when 

 fresh the surface is covered with a fine velvety epidermis. 

 Morum, Bolten, 1798 ; Ersina, Gray, and Lambidium, Link, are 

 synonyms. 



The few species occur in the West Indies, Galapagos, China, 

 etc. It is found in the eocene of Europe and miocene of N. 

 America. 



Section I. ONISCIA (sensu stricto). 0. oniscuis, Linn. Plesio- 

 niscia, Fischer, 1884, should be considered synonymous. 



Section II. ONISCIDIA, Swainson, 1840. 0. cancellata, Sowb. 



Genus PACHYBATHRON, Gaskoin, 1853. 



Shell small, subcylindrical, longitudinally striated ; spire very 

 short, but with sharp apex ; aperture narrow, very long, the inner 

 lip spread over the body-whorl and transversely plicate, the outer 

 lip thickened and .denticulated within. 2 sp. West Indies. P. 

 marginelloideum, Gask. 



Some conchologists place this group in the family Marginel- 

 lidae ; the dentition is unknown. 



Genus CASSIS (Klein, 1753), Lamarck, 1799. 



Section I. CASSIS, sensu stricto. 

 C. CORNUTA, Linn. PL 2, fig. 49 ; PI. 1, figs. 45, 46. 



Honey-combed between the revolving ridges, with three spiral 

 rows of distant compressed tubercles those of the shoulder the 

 most prominent ; yellowish white, more or less tinged with yel- 

 lowish brown, varices and belts sometimes brown-spotted ; colu- 

 mellar and lip expansion much produced and rounded behind, 

 yellowish cream-color, orange-brown within the aperture and 

 between the teeth, which are whitish. Length, 8-12 inches. 

 Indian Ocean, Tranquebar, Mauritius, Japan, 



Philippines; West Indies. 



Conrad distinguishes the West Indian specimens under the 

 name of C. labiata, Chemn., as being more oblong, with the lip 

 more widely expanded posteriorly into a flattened plane ; the 

 suite of specimens before me does not confirm this distinction. 



