142 BULLETIN 111, UNITED STATES NATIONAL MUSEUM. 



drawn. As heretofore observed in the case of Gadila the value of the 

 subgenus Cadulus is rather as an aid in grouping together a certain 

 number of species by reason of a general similarity of form. Its 

 biological significance is probably nil. 



There are eight species of western Atlantic Oadulus at present 

 known that clearly fall within the limits of this subgenus. They are 

 specifically determinable chiefly upon their relative degrees of obesity 

 and upon their size and general facies. A key would be of little use. 

 These are G. ampullaceus, 0. exiguus, G. ohesus, G. cucurbita, G. jjlaten- 

 sis, G. podogrinus, G. halius, and G. tersus. Three species, G. curtus, 

 G. congruens, and G. transitorius, occupy an intermediate position, 

 not having fully developed t:ie bulbous character of Cadulus s, s. 

 Their assignment to either Gadila or Gadulus is entirely arbitrary. 



CADULUS (CADULUS) CURTUS Watson. 



Plate 20, fig. 7. 



1879. Cadulus curtus Watson, Journ. Linn. Soc. London, voL 14, p. 527. 

 1885. Cadulus curtus Watson, Challenger Report (Scaphopoda), p. 21, pL 3, fig. 7. 

 1898. Cadulus (Gadila) curtus, PiLSBRYand Sharp, Tryon's Man. Conrh., vol. 17, 

 p. 175, pi. 25, fig. 60. 



The shell is short, broad, and semiobese, almost straight, narrowed 

 at both ends, with an approximately median swelling, giving to its 

 convex side a humpbacked appearance. The concave side is almost 

 a stright line, though curved a little posteriorly, and with a consider- 

 able convexity at the equator. The section is almost round. The 

 anterior aperture is rather large, slightly oblique, and has a thin 

 edge. The apical orifice is small. Apical characters are doubtful, 

 ''chipped." 



The type is in the British Museum and measures — ^Length, 2.5 mm. ; 

 diameter, 0.75 mm.; anterior aperture, 0.25 mm. (Watson). It was 

 taken by the GJiallenger at its station 24, off Culebra Island, in 390 

 fathoms, bottom of Pteropod ooze. 



This species is one of the numerous barrel-shaped forms placed 

 under the section Gadulus. There are no examples in the National 

 Museum collection, nor have I seen specimens. 



cadulus (CADULUS) CONGRUENS Watson. 



Plate 20, fig. 10. 



1879. Cadulus curtus congruens Watson, Journ. Linn. Soc. London, vol. 14, p. 527. 

 1885. Cadulus curtus congruens W ATSON , Challenger Heiport (Scaphopoda), pp. 21, 



22, pi. 3, fig. 7 (a). 

 1898. Cadulus curtus congntens, Pilsbry and Sharp, Tryon's ^^an. Conch., vol. 17, 



p. 175, pi. 25, fig. 59. 



The author describes his subspecies, here given full specific value, 

 by comparison with the type of Cadulus curtus. It is one-third larger 

 (length about 3.3 mm.) with less oblique aperture (?). The section 

 is round instead of being slightly compressed, as in typical C. curtus 



