MUSEUM OF COMPARATIVE ZOOLOGY. 429 



is much variation in the depth of the nicks at the posterior margin, ana rarely 

 there are six instead of four. Some are usually deeper than others, and they 

 are seldom as square as in the one figured. 



Cadulus sequalis Dall. 



Plate XXVII. Fig. 9. 



Cadulus ceoualis Dall, Bull. M. C. Z., IX. p. 34, 1881. 



Habitat. Station 43, in 339 fms., near Tortugas. 



This fine species is the least swollen of any of the forms from this region, 

 and only C. cylindratus Jeffreys, exceeds it in this particular. Its nearest rela- 

 tive is 0. spectabilis Verrill, which is larger, less cylindrical, more curved, and 

 more attenuated behind. 



Cadulus spectabilis Verrill. 

 C. spectabilis Verrill, Trans. Conn. Acad., VI. p. 432, pi. xliv. fig. 19, 1885. 



Habitat. Station 230, near St. Vincent, in 464 fms., sand, temperature 41°.5. 

 Southeast of George's Bank, Massachusetts coast, in 1400-1800 fms., U. S. 

 Fish Commission. 



The single specimen from St. Vincent is of a more even ivory white, and 

 rather less attenuated posteriorly, than the specimens from New England; 

 otherwise it seems to agree fairly well with them. 



Cadulus Watsoni Dall. 

 Plate XXVII. Fig. 12 a. 



Cadulus Watsoni Dall, Bull. M. C. Z., IX. p. 34, 1881. 



Habitat. Yucatan Strait, near Cape San Antonio, in 413 and 1002 fms. 

 Also off Old Providence, in 382 fms., ooze, temperature 46°. 0, at IT. S. Fish 

 Commission Station 2150. 



Cadulus poculum Dall. 



Shell about the size of C. Watsoni, but more curved ; the swollen equator 

 quite near the mouth, and the part of the shell in front of it sharply compressed 

 vertically, with the aperture very oblique, like the mouth of a whistle ; wider 

 than high ; surface polished, smooth ; posterior aperture small, circular, not 

 notched, but projecting slightly more at the sides than above or below. Lon. of 

 shell, 13.2; anterior margin over convex side to equator, 4.0; vertical diameter 

 at equator, 2.0 ; transverse ditto, 2.5 ; transverse diameter of posterior orifice, 

 0.63 ; of anterior ditto, 1.75 mm. 



Habitat. Off Cape San Antonio in 640 fms. Station 226, near St. Vincent, 

 in 464 fins., sand, temperature 42°.5 F. 



This shell is remarkable for the obliquity of the equator, and of the slope on 

 the convex side from the summit to the anterior margin. In these particulars 

 it is more strongly marked than any other species I have seen. The anterior 



