38 BULLETIN OF THE 



The sculpture of this species recalls that of D. capillosum Jeffreys, which is 

 a much larger species, less suddenly attenuated, and, so far as described, want- 

 ing in the remarkable color- pattern of D. sericatum. 



D. ceratum n. s. 



Shell of waxen hue becoming whiter toward the mouth, aculeate, slightly 

 curved, rather stout, and of glassy texture ; at the anal end septangular, the 

 angles passing into riblets at the beginning of the middle third, then becoming 

 gradually much more numerous, finer, fainter, and lastly absent or evanescent 

 on the oral third. Surface shining, apertures simple, circular. Lon. 30.0. 

 Anal diam. 0.5. Oral diam. 2.0 mm. 



West Florida, Pourtales, 50 fms. Station 2, 805 fms. 



This species has about the curve and proportions of D. circumcinctum 

 Watson, but is much smaller, has a wholly different sculpture and no anal 

 notch. 



B. — Species with tube laterally compressed. 



D. Sigsbeanum n. s. 



This may be best described by comparing it with its nearest ally, D. didy- 

 mum Watson (St. Thomas, W. I.), than which it is more slender, more attenu- 

 ated, more arched, and the compression results in an evenly elliptical section, 

 instead of a subtriangular one, as in his species. It is translucent whitish, less 

 brilliant than the last-described species, and apparently, from the look of 

 the eroded tips, is notched at the anal end, but this is not certain. Lon. 20.0. 

 Anal diam. 0.3. Major oral diam. 2.0. Minor do. 1.1 mm. 



Yucatan Strait, 640 fms. 



C. — Species with tube transverse/]/ compressed. 



D. compressum Watson. 



Station 43, 339 fms. ; off C. San Antonio, 413 fms. (Culebra, St. Thomas, 

 390 fms. — Challenger.) This turns out not to be a SiphonodeiitaUum, after all. 



D. ophiodon n. s. 



About the same length as the last species, more slender, more acute, mure 

 translucent, more curved, and without the evanescenl indications of longitu- 

 dinal striation ; the compression results in less tendency to angulation, and 

 there is an evident tendency, in adult specimens, tor the diameter at the month 

 to be somewhat Less than at a short distance behind it, —a very marked <lis- 

 tinction as between the two. The shell is quite translucent, and very thin ; 

 there is very little variation between the specimens. Lon. 12.5. Anal diam. 

 0.27. Major oral diam. 1.3. Minor do. 1.1 mm. 



