130 



BULLETIN 111, UNITED STATES NATIONAL MUSEUM. 



any trace of carination at the equator. The anterior portion of the 

 shell is somewhat flattened on its convex side. The larger aperture 

 is very oblique. The shell is semitransparent with many inner 

 translucent rings of shelly deposit especially in the posterior end, 

 or "neck." The apical characters show some modification from a 

 mere simple rim but they are not distinct. 



There is very little variation in size. 



The type, Cat. No. 314772 (a), U.S.N.M., measures— length, 7.75 

 mm.; diameter, 1.5 mm.; anterior aperture, 1 mm.; apical aperture, 

 0.5 mm. It was dredged at Eolis Station 340, off Fowey Light, 

 Florida, in 209 fathoms, bottom of fine sand. 



This seems to be an abundant species of the Floridian upper conti- 

 nental shelf zone within the Gulf Stream area. It strongly resembles 

 Cadulus amiantus but is larger. It is much larger than C. nitidus, 

 less inflated than C. lunula, and lacks the lateral compression of C. 

 lunula and C. simpsoni and the dorso-ventral compression of C. husMi. 



The following are the museum records: 



Subgenus GADILA Gray, 1847. 



1847. Gadila Gr.\y, Proc. Zool. Soc, p. 159. For full synonymy and discussion 

 thereon see Pilsbry and Sharp in Tryon's Manual of Conchology, vol. 17, 

 p. 162. 



These authors first defined the subgenus by description, as follows: 



Shell decidedly curved; more or less swollen near the middle or toward the aper- 

 ture; more tapering toward the apex; apical orifice not contracted by a callous ring; 

 or, with such callous ring, weak and far within. Edges not slit. (Pilsbry and Sharp.) 



The type is Cadulus gadus Montague. 



The essential characters of Gadila are first, the simple rim of the 

 apical orifice unmodified b}^ any slits or lobes and second, the slender- 

 ness of the shells. This second feature is of less importance for there 

 can be no strict division made between the more inflated forms of 

 Gadila and the less obese forms of Cadulus, s. s. 



