124 BULLETIN 111, UNITED STATES NATIONAL MUSEUM. 



ent from others of the group so far observed. Although the equator 

 is less anteriorly placed, this species belongs to the group of Cadulus 

 elongatus. It is named after Capt. S. W. Greenlaw, master of the 

 Eolis. Both this species and C. elongatus are greatly lengthened 

 and very slender forms of a conventional type of Cadulus, and are 

 not to be associated with the rather bizarre group that includes C. 

 acus and C. dominguensis. 



CADULUS (PLATYSCHIDES) ARCTUS. new species. 



Piate 19, fig. 19. 



The shell is exceedingly slender, very slightly flattened, moderately 

 curved, slightly swollen, with a very small apical orifice and a small 

 contracted oblique anterior aperture. The equator is at the anterior 

 fourth and represents the point of maximum section rather than a 

 local swelling. The convex side has an evenly arched outhne almost 

 unmodified at the equator although the cylinder is flattened on this 

 side from the equator to the larger aperture. The concave side is 

 more strongly curved posteriorly and shows a sHght bulge at the 

 equator; its posterior three-fourths tapers to an attenuated apical 

 opening. The anterior aperture is transversely oval, with a rather 

 sharp peristome. The apical orifice is almost round. The apical 

 characters are not clearly shown in any of the Museum specimens. 

 Measurements are: 



Length, 11 mm.; diameter, 1.60 by 1.40 mm.; anterior aperture, 

 1 mm.; apical aperture, 0.40 mm. (type). 



Length, 9 mm.; diameter, 1.50 by 1.20 mm.; anterior aperture, 

 0.90 mm. ; apical aperture, 0.40 mm. 



The type. Cat. No. 323955, U.S.N.M., was taken at the U. S. B. F. 

 Station 2404 in the Gulf of Mexico, off Cape San Bias, Florida, in 

 60 fathoms, bottom of gray sand. 



There are 10 specimens in this and one other lot, Cat. No. 151830, 

 from the same station. This is a unique record. 



Cadulus arctus is one of the most gracefully formed species of the 

 genus. Its extreme slenderness and finely drawn out apical portion 

 make it quickly recognizable among aU other Caduli from the same 

 region, 



CADULUS (PLATYSCHIDES) BRAZILIENSIS, new species. 



Plate 19, fig. 16. 



The shell is elongate, slender, round, slightly curved, with its 

 section of maximum diameter at about the anterior one-fifth, and is 

 unmarked by any local swelling. The convex outline describes a 

 regular arch, though slightly straightened between the equator and 

 the anterior aperture, which area is a little flattened. The concave 

 outline forms almost a curve, though rather straighter in its anterior 

 half, and with no convexity or even interruption at the equator. 



