EAST AMERICAN SCAPHOPOD MOLLUSKS. 113 



ures: Length, 8.6 mm.; diameter, 2 by 1.75 mm.; anterior aperture, 

 1 by 1.2 mm.; apical aperture, 0.75 by 1 mm. 



There are no examples in the National Museum collection. The 

 median position of the equator, the localized swelling, the oval aper- 

 ture, and the flattened, large apical orifice, are the chief characters 

 of the species. A medium-power lens shows in an oblique light five 

 transverse scratches on the polished vitreous surface, but these are 

 hardly sufficient for diagnostic value. Its nearest ally is probably 

 Cadulus agassizii, from which species, however, the median equator 

 of C. catharus separates it. 



CADULUS (PLATYSCHIDES) PARVUS, new species. 



Plate 18, figs. 2, 4. 



1889. Cadulus amiantus Dall, Bull. Mus. Comp. Zool., vol. 18, p. 431, in part and 



omitting figure. 

 1889. Cadulus amiantus Dall, Bull. 37, U. S. Nat. Mus., p. 78. 

 1898. Cadulus amiantus, Pilsbry and Sharp, Tryon's Man. of Conch., vol. 17, p. 



174, in part and omitting figure. 

 1903. Cadulus amiantus Dall, Bull. 37, U. S. Nat. Mus., p. 78. 



A few lots in the National Museum collection that have been re- 

 ferred to Cadulus amiantus, together with some recently added lots 

 from the Florida Keys region and from Barbados, upon careful com- 

 parison with the type of C. amiantus, must be renamed. 



The following description is from a Barbados specimen: The shell 

 is small, with a large, open, and gaping apical orifice and an oblique 

 anterior aperture, very little, if any, larger than the posterior orifice. 

 The equator is about median and without any local swelling. The 

 convex outline forms a fairly regular arch, though it is somewhat 

 flattened anteriorly. The concave outline is marked by a slight con- 

 vexity at the equator. The shell is a little flattened on the concave 

 side near the apical orifice and in the extreme posterior portion, im- 

 parting to it an oval shape; within this opening are some callous 

 rings. The apical opening is modified by some shallow slits and 

 broad, ill-defined lobes. Measurements are: 



Length, 5.8 mm.; diameter, 1.1 mm.; anterior aperture, 0.8 mm.; 

 apical aperture, 0.7 mm. (type). 



Length, 5.5 mm.; diameter, 1.05 mm.; anterior aperture, 0.8 

 mm. ; apical aperture, 0.7 mm. 



Length, 6 mm.; diameter, 1.1 mm.; anterior aperture, 0.8 mm.; 

 apical aperture, 0.8 mm. 



This species groups with C. agassizii by reason of possessing the 

 same flattened, large, and gaping posterior orifice, with an identical 

 arrangement of apical slits. The chief difference lies in the smaUer 

 size of C. parvus, some specimens of which may slightly exceed 6 mm. 

 in length, but the smallest C. agassizii are about 7 mm., with an aver- 



