104 COLTJMBELLA. 



the Cretaceous and Jurassic columbelloid shells belonging to 

 distinct genera. 



Section 1. Columbella (fypical). 



Shell strombiform, smooth, with short spire. 

 C. STROMBIFORM is, Lam. PI. 42, figs. 5-10. 



Shell strombiform, the body-whorl much swollen around the 

 upper part and somewhat produced at the posterior end of the 

 aperture; chestnut-color, with the spire and middle and lower 

 portion of the body-whorl minutely white-spotted ; sometimes 

 the spots coalesce into zigzag white markings ; there are also 

 usually a few irregular large white spots on the shoulder or 

 middle of the body-whorl ; interior usually white, sometimes 

 orange-tinted ; epidermis thick, shaggy, longitudinally striated, 

 frequently decussated posteriorly or throughout by revolving 

 striae ; operculum very variable in form, the initial point usually 

 terminal and basal but occasionally even subcentral, or marginal 

 at the centre of its length. Length, '831*4 inches. 



West Coast of Central America to Mazatlan; Gulf of California. 



With this species is to be united C. major, Sowerby (figs. (J-S), 

 which Carpenter and others have suspected to be a variety, having 

 dots instead of the zigzag white markings and the spiral sculpture 

 of the epidermis on the shoulder only, instead of all over; neither 

 these, nor the other inferior distinctive characters given, hold 

 good when a large series of specimens is examined. Fig. 8 

 represents a smaller, but adult shell ; it is a minor race, which, 

 as in so many of the species of mollusks usually accompanies 

 the normal-sized individuals. Other synonyms are C. gibbosa, 

 Duclos (tig. 9), C. Bridgesi, Reeve (tig. 10), not full grown. 



C. PAYTENSIS, Lesson. PL 42, figs. 11-14. 



Whorls broadly channeled below the sutures: chestnut-brown, 

 minutely dotted with white throughout. Length, 1-1 '15 inches. 



Payta, Peru; Chili. 



This may possibly be a variety only, of the preceding species ; 

 the sutural channel is strongly marked, however, in the numerous 

 specimens before me. G. spurca, Sowb., C. runtira, Sowb. 

 Genera of Shells (fig. 14), and C. Paytalida, Duclos (fig. 13), are 

 synonyms. 



