168 CADULUS-GADILA. 



Yucatan Strait, near Cape San Antonio, in 413 and 1,002 fms. 

 (Blake) ; also of Old Providence, in 382 fms. (U. S. Fish Commis- 

 sion). 



Cadulus watsoni DALL, Bull. M. C. Z., ix, p. 34 (1881) ; xviii, 

 Blake Rep., p. 429, pi. 27, f. 12a (1889) ; Bull. U.S. Nat. Mas., No. 

 37, p. 76. VERRILL, Trans. Conn. Acad. Sci., vi, p. 219 (1884). 



It is reported from off Cape Hatteras by Verrill, who compares 

 the species to C. pandionis. The greatest diameter is contained 4 

 times in the length in C. watsoni. In C. rushii it is decidedly less, 

 being contained nearly 6 times in the length, and the tube is less 

 compressed at the equator. ' 



C. RUSHII Pilsbry & Sharp, n. sp. PL 27, figs. 94, 95, 96, 97. 



Shell moderately solid, large, moderately arcuate, the bend mainly 

 posterior ; outline of convex side almost evenly arched, but more 

 convex near the larger end ; outline of opposite side nearly straight 

 along the anterior half, the posterior half decidedly concave ; great- 

 est diameter contained 5?-6 times in the length of shell. Swelling 

 quite moderate, greatest at about the anterior fourth of the length, 

 thence tapering gently to the aperture, and decidedly toward the 

 apex, the posterior half of the shell being conspicuously attenuated. 

 Tube compressed between the concave and convex sides throughout. 

 Surface glossy and smooth ; opaque white. Aperture quite oblique, 

 subcircular, but viewed in line with the axis of the latter portion of 

 the tube it is oval. Apex small, rounded-oval, its margin even. 



Length 11*6 ; antero-posterior diameter at aperture 1*4, at great- 

 est swelling 1*8, at apex 0'53 mill.; lateral diameter at aperture 1*6, 

 at greatest 2*0, at apex 0'6 mill. 



Off Cape Hatteras, lat. 35 1$ 30", long. 75 IJf 12", in 293 fms. 

 (Dr. W. H. Rush). 



The equator is more anterior than in C. pandionis, and the swell- 

 ing decidedly less in proportion to the length of the shell. The 

 tube is less flattened vertically than in C. ivatsoni Dall, the aperture 

 a shorter, rounder oval, and the whole shell more slender. 



There is generally no noticeable callous ring within the anal 

 opening, but in some specimens a very slight one, far within, seems 

 to be developed. 



C. AGASSIZII Dall. PL 25, fig. 57. 



Shell translucent white, with more opaque annulations, shining, 

 destitute of sculpture, excepting nearly imperceptible lines of growth, 



