36 BULLETIN OF THE 



out perceptible sculpture ; neither of the apertures appears to be oblique ; 

 both are circular. Lon. 4.0. Max. diam. 1.25. Oral diani. 0.62. Anal diam. 

 0.37 mru. 



Station 19, 310 fms. 



It is really somewhat difficult to decide which is the anterior opening in this 

 species, unless the size be considered a criterion. 



C. sauridens "Watson. 



St. Thomas, Challenger Exp., 390 fms. Blake Exp., Station 19, 310 fms. ; 

 off Cape San Antonio, 1,002 fms. Barbados, Hassler Exp., 100 fms. 



C- obesus Watson. 

 St. Thomas, Challenger Exp., 390 fms. Blake Exp., Station 20, 220 fms. 



Siphonodentalium quadridentatum n. s. 



This species is best described by comparing it with S. tetraschistum Watson, 

 to \Vhich it is nearly allied. The present form, which may prove eventually to 

 be a large race of Watson's species, seems to differ from it in its proportionately 

 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 quadridentatvm are: — Lon. L0.0. 

 Max. diam. 1.3. Oral diam. 0.80. Anal diam. 0.4 mm. The same in Mr. 

 Watson's species are 7.7, 0.81, 0.75, and 0.4 mm. respectively. His specimen 

 came from Fernando Noronha, 7-25 fms. ; ours is from Pourtales's dredginga 

 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. 



DENTALIUM. 



A. — Species with cylindrical tube. 



D. perlongum Dam. 



Bull. Mus. Cottp. Zool., V. No. 6, p. 01 (name only). 1S78. 



Shell solid, opaque white. Bhining, without sculpture except delicate irrego* 

 larities due to incremental lines; oral aperture simple, nearly circular, its plane 

 quite or nearly at righl angles to the axis ; anal aperture with a shallow notch 

 (in adult specimens) on the convex Bide ; tube very slightly curved. Lon. 

 BO.O t., BOA Anil diam, ".:■ t.. ik7. Oral diam. 3.8 mm. 



Station 41, 860 fma station 16, 888 fms. Yucatan Strait. 640 fma, Sta- 

 tion :;::. hat. 84° l'. Lon, B8° B8' \\\, 1,568 fms. 



