150 CADULUS-POLYSCHIDES. 



" This species is best described by comparing it with S. tetraschis- 

 turn Watson, to which it is Dearly allied. The present form, which 

 may prove eventually to be a large race of Watson's species, seems 

 to differ from it in its proportionally greater stoutness and actually 

 larger size, in the want of any sculpture on its polished surface, and 

 in the proportionally smaller and narrower slits at the anal end of 

 the tube. The dimensions of quadridentatum are: Lon. lO'O, max. 

 diam. 1*3, oral diam. 0'8, anal diam. 0'4 mill. The same in Mr. 

 Watson's species are 7'7, 0*81, 0'75 and 0'4 mill, respectively. His 

 specimens came from Fernando Noronha, 25-fms. ; ours is from 

 Pourtales' dredgings on the west coast of Florida in 30 fms. 



"In other respects than those mentioned, Watson's description 

 and figure agree almost exactly with our specimen" (Dall, 1881). 



The original description here follows of 



Var. incisus Bush. PL 25, fig. 65. 



"Shell rather small, slender, somewhat cylindrical, slightly con- 

 tracted dorsally, just back of the anterior aperture, tapering and 

 curving gradually from about the middle toward the posterior end. 

 It is thin, semitransparent and very lustrous. Anterior aperture 

 is oval and a little oblique ; the posterior aperture is very ob- 

 lique with four narrow very deep notches, two on each side, form- 

 ing four conspicuous points on the end of the shell. Length of 

 largest specimen 8, diam. anterior aperture 1, posterior aperture 0*5 

 mill. The other specimen is smaller and more slender, measuring, 

 length 7, diam. anterior aperture 0'8, posterior less than 0'5 mill." 

 (Bush*). 



This form is from the Hatteras region. 



C. QUADRIFISSATUS (Carpenter), n. sp. PI. 29, figs. 10, 1 1, 12, 13. 



Shell arcuate, the bend greater posteriorly, slender, but slightly 

 tapering, not swollen, subtransparent bluish, with a milky band near 

 the larger end ; smooth and rather glossy, the growth lines hardly 

 visible; posterior third slowly tapering, the tube then nearly cylin- 

 drical almost to the aperture; quite near the latter it is contracted, 

 the contraction greatest on the convex side. Greatest diameter 

 contained about 7 times in the length of the shell. Aperture ob- 

 lique, transversely oval; apex cut into four conic teeth by the same 

 number of short slits ; the tooth on convex side slightly longest,, 

 the other three subequal in length, that on concave side wider and 

 obtuse ; edges of the teeth somewhat bevelled distally. 



