EAST AMERICAN SCAPHOPOD MOLLUSKS. 123 



ceptible convexity at the equator. The lateral outhnes are almost 

 straight, diverging but slowly from the very small apex through the 

 long ''neck" of the shell to its section of maximum diameter, thence 

 converging slowly through the short remaining distance to the larger 

 aperture. On the convex side the shell is much flattened between 

 the equator and the very obhque aperture, causing its peristome to 

 describe an irregular oval. Throughout, the shell is somewhat com- 

 pressed, even the apical orifice showing a slightly flattened circle. 

 Apical characters are not clearly sho^vai, but a slight flare of the rim 

 with certain irregularities indicate a probable PlatyscJiides affiliation. 



The type. Cat. No. 323596, U.S.N.M., measures— length, 14.10 

 mm.; diameter, 1.50 by 1.75 mm.; anterior aperture, 1.40 by 1 mm.; 

 apical aperture, 0.4 mm. It was dredged at the U. vS. B. F. Station 

 2378, off the mouth of the Mississippi River, in 68 fathoms, bottom 

 of gray mud. It is a unique specimen. 



This species is easily recognizable by its extreme length and slen- 

 derness. At first glance it might be associated with Cadulus acus 

 but it belongs rather to the group of O. arctus and C. hraziliensis. 

 The shell is curiously marked ])y l^roken circles of opaque ivory 

 white alternating with translucent ones. I do not, howev^er, believe 

 this to be a specific character. This same feature may be noted in 

 C. hraziliensis. 



CADULUS (PLATYSCmOES) GREENLAWI. new species. 



Plate 18, fig. 11. 



The shell is rather strongl}'' curved, elongate, very slender, gradu- 

 ally increasing from a very small apical orifice to the equator, which 

 is located at about the anterior one-third; thence the caliber of the 

 shell rather suddenly contracts and then more slowly diminishes to 

 the anterior aperture. The entire shell is somewhat compressed 

 except near the apical end, where the section is round. The convex 

 outline describes an even curve, though a little straightened from 

 the equator to the larger aperture. The concave outline is more 

 strongly arched posteriorly and is slightly bulged out at the equator. 

 From the equator anteriorly the cylinder is decidedly flattened, im- 

 parting to the anterior aperture a transversely oval shape. -The 

 swelling at the equator is localized by reason of the contraction ad- 

 joining it anteriorly. The apical features are not clearly shown. 



The type, Cat. No. 314767, U.S.N.M., measures— length, 11 mm.; 

 diameter, 1 by 1.25 mm.; anterior aperture, 1 mm.; apical aperture ^ 

 0.25 mm. It was dredged by the Eolis at its Station 380, off Fowey 

 Light, Florida, in 130 fathoms, bottom of green mud. The type is 

 the only specimen. 



Unfortunately the aperture of the unique specimen is injured and 

 can not be described, but there is no reason to suppose it to be differ- 

 157582°— 20 -9 



