EAST AMERICAN SCAPHOPOD MOLLUSKS. 125 



The lateral lines diverge slowly from a narrow small apical orifice to 

 the equator, the exact position of which, when viewed on the concave 

 side, is rather indefinite, and thence they converge more rapidly to 

 the relatively broad anterior aperture. This aperture is considerably 

 flattened on its convex side, giving to it an irregularly oval outline; 

 it is also very obKque. The apical characters are not clearly shown, 

 but seem not to be perfectly simple. 



The type, Cat. No. 96113, U.S.N.M., measures— length, 8.50 mm.; 

 diameter, 1.10 to 1.20 mm.; anterior aperture, 0.8 by 1 mm.; apical 

 aperture, 0.35 mm. It was dredged by the Albatross at the U. S. 



B. F. Station 2762, east of Rio de Janeiro, in 59 fathoms, bottom of 

 mud, temperature 57°, and is from a lot of two specimens. 



One specimen exhibits a series of opaque white rings alternated 

 by translucent spaces like zebra stripes. The type shows the same 

 conditions in a modified degree. This species belongs in a group 

 with Cadulus arctus and C. elongatus and those other species charac- 

 terized by a slight expansion of the diameter at an anteriorly placed 

 equator. From this group must be excluded, of course, those 

 species of similar shape, but which fall under Polyschides by reason 

 of their special apical characters. 



The remaining species oi Platyschides are not easily grouped, though 

 each possesses some characters similar to those of one or another of 

 the groups heretofore considered; these are Cadulus hushii, C. lunula, 



C. simpsoni, C. miamiensis , C. amiantus, and C. nitidus. « 



CADULUS (PLATYSCmOES) BUSffll Dall. 



Plate 19, fig. 10. 



1889. Cadulus carolinensis hushii Dall, Bull. Mue. Comp. Zoo!., vol. 17, p. 430. 

 1898. Cadulus (Polyschides) carolinensis hushii, Pilsbry and Sharp, Tryon's Man. 



Conch., vol. 17, p. 153, pi. 33, figs. 58, 59. 

 1901. Cadulus (Polyschides) carolinensis hushii Dall and Simpson, Bull. U. S. 



Fish Com. for 1900, vol. 1, p. 457. 



The shell is small, thin, moderately curved, with a small apical 

 orifice, rather quickly expanding to the point of maximum diameter, 

 situated at about the anterior third, thence narrowing to a somewhat 

 constricted oblique anterior aperture. The convex side describes an 

 almost uniform arc, save for a very slight bulge at the equator; the 

 concave side shows its greatest curvature in its posterior third; there- 

 after it is almost straight but with a well marked convexity at the 

 equator. There is a constriction just back of the larger aperture, 

 vvhich is quite oblique and with a rounded peristome. The cylinder 

 is considerably compressed, causing the apical orifice to be somewhat 

 oval, though the anterior aperture is round. Viewed ventrally, the 

 lateral sides taper evenly from a wide equator posteriorly to the 

 small apex and anteriorly to the larger aperture. The apical features 

 are not clear in the type. Measurements are: 



