EAST AMERICAUT SCAPHOPOD MOLLUSKS. 145 



The shell is exceedingly small and bulbous, both the convex and 

 "concave" outlines being very convex, though not equally so. The 

 apertures appear to be but mere contractions at opposite ends of a 

 bulbous swelling, forming two short projecting tubes. The equator 

 is postmedian. The anterior aperture is large and slightly oblique. 

 The apical orifice is slightly oval and smaller than the other, and is 

 narrowed inside by a callous ring, reducing its caliber by about 

 one-half. The margin of this ring is "formed by the projecting end 

 of a short pipe, which passes up into the interior of the shell." No 

 apical features are mentioned by the author. Measurements are: 



Length, 2 mm.; diameter, 1.17 mm.; anterior aperture, 0.5 mm.; 

 apical aperture, 0.4 mm. (Watson.) 



The shell -"differs from exiguus in being rounder, has no tube 

 anteriorly, is not nearly so elongated posteriorly, and is provided 

 with a distinct posterior pipe." (Watson.) 



The type is in the British Museum and was taken by the Challenger 

 at station 24, off Culebra Island, in 890 fathoms, bottom of Pteropod 



ooze. 



There are no specimens in the National Museum collection posi- 

 tively referable to this species. It is known to me only by Watson's 

 description and figures. In this form the very extreme of the bulbous 

 shell is reached. 



CADULUS (CADULUS) EXIGUUS Watson. 



Plate 20, fig. 9. 



1879. Cadulus exiguus Watson, Journ. Linn. Soc. London, vol. 14, p. 528 

 1885. Cadulus exiguus Watson, Challenger Report (Scaphopoda), p. 23, pi. 3, fig.lO. 

 1898. Cadulus {Cadulus) exiguus, Pilsbry and Sharp, Tryon's Man. Conch., 

 vol. 17, p. 159, pi. 25, fig. 61. 

 The shell is very small, short, inflated, the bulbous swelling pinched 

 in to form two projecting short tubes at the posterior and the anterior 

 ends; the posterior tube being the smaller. The anterior aperture is 

 large, not oblique, and thin edged. The apical orifice is small and nar- 

 rowed within by an opaque callous ring forming a minute circular shelf. 

 The apical features are described as "chipped." Measurements are: 

 Length, 1.9 mm.; diameter, 0.875 mm.; anterior aperture, 0.4 mm.; 

 apical aperture, 0.25 mm. (Watson.) 



The type is in the British Museum and was taken by the Challenger 

 at Station 24 off Culebra Island, in 390 fathoms, bottom of Pteropod 



ooze. 



A single specimen in the museum collection. Cat. No. 216663, 

 U.S.N.m"., is from the Bahamas, collected by the Albatross, but 

 without station number or other record, and is referable to this 

 species. One specimen was taken by the State University of Iowa 

 Expedition at station 10, off Bridgetown, Barbados, in 100 fathoms. 



