34 BULLETIN OF THE 



It can hardly be expected that all the species here described will ulti- 

 mately prove to be new, but the probability is that most of them are 

 so. In preparing the descriptions, I have been much indebted to the 

 kindness of Mr. K. J. Boog-Wateon, in charge of the " Challenger " mol- 

 lusks, for early copies of his preliminary descriptions, etc., which has 

 enabled me to avoid re-describing species obtained by that expedition, 

 but of which knowledge in many cases has reached but a limited circle 

 of the scientific world. To Dr. J. Gwyn Jeffreys I am also under obli- 

 gations of a similar nature, and for the most obliging loan of rare and 

 even unique specimens for comparison. 



I may add that, so far, the more detailed study of the specimens has 

 done nothing to vitiate the deductions reached in the " General Conclu- 

 sions " (Bull. M. C. Z., VI. No. 3), but, on the contrary, the views there 

 put forward have received further confirmation. 



The difference in richness between the collections of the " Blake " and 

 those of the " Challenger " is truly remarkable, at least so far as the 

 mollusks are concerned ; the former containing perhaps three times as 

 many species as the whole three years' voyage of the "Challeuger" 

 brought to light. 



Cadulus aequalis n. s. 



Shell opaque white, polished, without sculpture except a rare line due to 

 growth or some irregularity ; very slightly curved with hardly any gibbosity 

 perceptible, such as there is being in the anterior fifth of the shell ; anal 

 opening circular, simple, thin-edged, not oblique ; anterior opening somewhat 

 oblique, slightly contracted, nearly circular ; the shell on the whole tapering 

 regularly toward the posterior end, which is stouter than usual in the genus. 

 Lon. 1"><>. Anal diaiii. 1.0. Oral diam. 2.0. Max. diam. 2.5 mm. 



Station 43, 339 fathoms, three specimens. 



This species is unlike any of those described from the "Challenger" col- 

 lections and the others figured by Sars. Its even taper is particularly no- 

 ticeable. 



Cadulus Watsoni n. s. 



Shell translucent white, polished, showing faintly the annular lines of 

 growth; slightly curved, with the greater portion of the curve in the anal 

 third ; tapering rapidly from the oral third to the posterior end; the oral 

 third Battened on the convex side toward the mouth ; this portion also tapered 

 laterally in the same direction ; oral aperture not perceptibly oblique in the 

 motl perfect specimen, slightly bo in another; the transverse diameter of the 

 mouth very slightly longer than the vertical diameter. Loa 13.0 j anal 

 diam. 0.6; oral diam. 1.6; max. diam. 2.26; these measurements, when not 



