< \ I i< UNA. 21Mf 



tin* middle. taperinL: t<\\ard tin- po-terior end and hn.adly rounded 

 iti front. >o that tlit' outline is somewhat conical, but truncated pos- 

 teriorly. At tin- tip then- is a >mall, hut rather deep pit. The 

 outer lip is thickened, and -omewhat constricted In-low the middle 

 and then slightly expanded and broadly rounded anteriorly: 

 teri-.rjy it bends inward and projects sliglitly beyond the tip of the 

 shell, and forms a distinct, rounded, posterior -inn-. The eolumella 

 margin is thickened, without a fold, and moderately exenrved. Th- 

 uinhilicus is narrow but deep. The aperture, in front of the middle, 

 is moderately broad and ovate, but further back it is much nar- 

 rowed and encroached upon by the bodv-whorl. The surface is 

 smooth and polished, without any sculpture except a few faint -piral 

 lines close to the posterior end and others which are wavy and even 

 less distinct at the anterior end. Color of the type-specimen, pure 

 white, with a very thin yellowish-white epidermis on some parts. 

 Length 6 mill.; greatest breadth, 4 mill.; length of aperture equal 

 to that of the shell ; its greatest breadth, 1*8 mill. ( F.)- 



Station 2265, off Cape Hatterat, in 70 fathom-. 



Cyliehna eburnea V., Tr. Conn. Acad. vi, p. 428, pi. 44, f. 14. 



This species is readily distinguished from all others of our coast 

 by its thickness and solidity, by its distinct umbilicus and by the 

 evident pit at the posterior end. In form it somewhat resembles 

 Diaphana conulus but it is less narrowed posteriorly, besides being a 

 much larger and stouter shell. (V.) 



C. DISCUS Watson. PL 30, fig. 7. 



Shell narrowly cylindrical, truncated in front like f alba 



(Brown), smooth, thin, polished, with a small disk-like minutely 

 perforated top. Sculpture: Longitudinals there are very faint 

 and slight lines of growth. Spirals there are some very doubtful 

 indications of a coarse spiral structure in the texture of the -hell. 

 Colour milky-white and glossy. Mouth the full length of the shell 

 but not more, extremely narrow with lips nearly parallel till they 

 diverge in front, the inner lip following the slow basal contraction, 

 while the outer expands a very little, as is the case in 

 bilicata (Mont.) ; at the upper end is a small narrow, l.ut deepish 

 rounded sinus. Outer lip: its edge i> very -traiirht. retreating a 

 little quickly above and slightly in front : its direction i- -trai^ht. 

 with the very slight bend to the ri_irht spoken of above. Top a little 

 contracted, rounded, with a sort of thickened pellucid di.-k which is 



