CADULUS-GADILA. 193 



the wrinkles small and very close. Branchial aperture simple. 

 Length 005, breath 0005-0-01 inch." (Cpr.). 



Mazatlan, on Spondylus calcifer. 

 C. ABERRANs Whiteavcs. PL 85, fig. 16. 



Shell slender, moderately but distinctly curved, large and much 

 elongated for the genus, increasing very slowly but regularly in 

 diameter, not distinctly (if at all) swollen in advance of the middle, 

 and very slightly and scarcely perceptibly constricted immediately 

 behind the aperture. Test extremely thin, surface polished, very 

 glossy and shining, smooth to the naked eye, but under a lens it is 

 seen to be marked with minute and transverse but somewhat oblique 

 lines of growth ( Whiieaves). 



Length of an average full-sized example 13*5 mill., greatest 

 breadth of the same near the anterior end 1'3 mill. ( Whiteaves). 



Quatsino Sound, British Columbia, abundant (AVhiteaves). 



Cadulus aberrans Whiteaves, Trans. Roy. Soc. Canada, iv. Sect. 

 4, p. 124, f. 2 (1887).— Taylor, Ibid. (ser. 2), i. Sect. 4, p. 56. 



This little shell, which is, nevertheless, of large size for the genus, 

 looks not unlike an immature Dentalium, and, at first sight, speci- 

 mens of it might be easily mistaken for half-grown examples of D. 

 'pretiosum Nuttall, which the Indians say occurs at the same local- 

 ity. It may, however, be distinguished from any Dentalium by its 

 thin test and highly polished outer surface, though the swelling of 

 the shell in advance of the middle and the constriction behind the 

 aperture which are usually marked characters in the genus Cadulus,. 

 are reduced to a minimum in this species, and in most specimens are 

 quite imperceptible ( Whiteaves). 



C. fusiformis Pilsbry & Sharp, n.sp. PI. 35, fig. 14. 



Shell but little curved, long and slender, the greatest diameter 

 contained about 9 times in the length of the shell ; swelling hardly 

 perceptible, the tube very gradually enlarging from the small apex 

 to the beginning of the last third of the length, thence an equal size 

 is maintained almost to the aperture, just before which it is gently 

 but quite perceptibly contracted on all sides. Surface smooth and 

 glossy, bluish-white, scarcely translucent, with oblique rings of more 

 opaque white, and near the apex some longitudinal white lines ; a 

 pellucid ring bordering the lip-edge, behind which there is a short, 

 opaque white tract, passing gradually into the bluish and banded 

 general color. Tube a mere trifle compressed vertically at the 

 13 



