170 CADULUS-GADILA. 



It is also somewhat allied to C. watsoni in shape and proportions^ 

 but our form is not " flattened on the convex side toward the mouth," 

 and the equator is subcircular, but little greater in transverse than 

 in vertical diameter. The callous ring within the vertically com- 

 pressed apical orifice is a conspicuous feature in hatter asensis. 



C. ^EQUALIS Ball. PI. 25, fig. 48. 



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 ante- 

 rior 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. Length 

 15 mill., oral diara. 2 mill., anal 1 mill. ; maximum diameter 2*5 

 mill. (Dall). 



Near Tortugas, in 339 fms. (Blake). 



C. cequalis DALL, Bull. Mus. Comp. Zool., ix, p. 34 (1881) ; Ibid., 

 xviii, p. 429, pi. 27, fig. 9 (1889) ; Bull. U. S. Nat. Museum, No. 

 37, p. 76, pi. 27, f. 9. 



This fine species is the least swollen of any of the forms from this 

 region, and only C. cylindratus Jeffreys exceeds it in this particular. 

 Its nearest relative is C. spectabilis Verrill, which is larger, less 

 cylindrical, more curved and more attenuated behind (Dot//). 



C. OLIVI (Scacchi). PL 31, figs. 33, 34, 35. 



Shell rather thin, moderately curved, the bend mainly posterior; 

 moderately swollen, the " equator " indistinctly angular, at the ante- 

 rior third of the length, slightly oblique ; thence tapering moder- 

 ately to the mouth, and more rapidly posteriorly, becoming attenu- 

 ated toward the apex. Outline of concave side slightly modified, 

 becoming a trifle convex in the region of greatest inflation. Great- 

 est diameter contained 5 times in length of the shell. Tube very 

 slightly compressed between front and back curves. Surface polished, 

 without perceptible growth-striation. Aperture oblique, rounded 

 oval ; anal orifice subcircular, its edge even, unslit. 



Length 11-7 mill.; diam. at aperture l'24x 1'37, at greatest infla- 

 tion 2-06 x 2*33, at apex 0-48 x 0-55 mill, (the antero-posterior di- 

 mensions given first in each case). 



Pliocene of southern Italy and Sicily ~ 



