50 TJniversity of Michigan 



lobate at parietal angle and quite markedly aurieulate at basal 

 angle ; but very slightly expanded in eolumellar region ; thick- 

 ened internally hj continuous caUus, which, however, is thin 

 in the parietal and very narrow in the eolumellar region. 



Operculum : 314 whorls ; similar to that of T. aurantia, but 

 with calcareous portion much thinner ; calcareous plate closely 

 applied to horny base; externally the nuclear concavity and 

 the linear convexity are much less prominent than in aurantia. 



Radula : similar to muskusi. 



Measurements 



Shell Aperture Operculum Whorls 



alt. maj.diam. min.diam. alt. diam. long wide 



male 10.5 60(6.3) 47(4.9) 45(4.7) 92(4.3) 35(3.7) 73(2.7) 4% 

 female 



(tvpe) 14.0 54(7.6) 44(6.2) 44(6.2) 84(5.2) 34(4.7) 77(3.6) 514 



Tudora rupis newportensis, new subspecies 

 Type locality: (CI) along road, just north of New Port, 

 Curasao. 



Distribution : Curacao ; probably occurs on the more recent 

 limestone all along the west shore, south of Spaansche Baai. 

 Very common; on trees and brush and under rocks. 195 

 specimens collected. 



Shell (fig. xii-D) : considerably larger but relatively thin- 

 ner than rupis. Color : like rupis, but spiral bands, although 

 sometimes absent, usually are more distinct and more com- 

 monly continuous ; almost alwaj's with at least one continuous 

 band surrounding the umbilicus from just below the parietal 

 angle of the aperture. Whorls: usually more than 4% 

 retained. Last whorl (fig. x-30) : growth-threads regular, 

 closely-spaced, low and rounded, often so broad and coalescent 

 as to render the surface practically^ smooth ; spiral sculpture 

 typically obsolescent except in umbilical region, where it de- 

 velops low, rounded ridges, always surmounted by the growth 

 sculpture. Earlier whorls: growth sculpture closely resem- 

 bling that of aurantia ; spiral sculpture very obscure. Peristo- 

 mal callus: thinner than in rupis. Operculum: 3^^ whorls. 

 Other characters as in rupis. 



