VITKINELLA. Pancbma Shells. 187 



more than three, convex above and concave below the middlej 

 with a distinct suture : aperture orbiculat : labrum angulated 

 externally by the spiral ridges, a little thickened : umbilicus 

 deep, narrow. A variety has the ridge aroiind the umbilicus 

 well developed. 



Mean divergence about 160° ; greatest breadth .07 inch ; 

 least breadth .06 inch ; height ,04 inch. 



Station. — Unknown. 



Habitat. — ^Panama ; 0. B. A. I 



24 specimens were found in the calcareous sand. 



264. Titrinella parra. Nov. sp. 



Shell subdiscoidal : white : with numerous stout prominent 

 transverse ribs ; with, on each side of the periphery of the last 

 whorl, a not very prominent keel, of which the upper one is 

 visible on the spire : apex very obtuse : spire convex, slightly 

 elevated: whorls three and a hal^ angular above, concave 

 between the an^le and the keel, with the suture not very dis- 

 tinct ; last whorl very large : aperture orbicular, very oblique 

 in consequence of the advaftce of the labrum above : lip 

 slightly thickened: umbilidus deep, narrow. This species 

 resembles V. Panametisis. 



Mean divergence about 160° ; greatest breadth .047 inch ; 

 least breadth .04 inch ; height .026 inch. 



Station. — Unknown. 



Habitat. — Panama ; Ov B. A. I 



13 specimens were found in the calcareous sand. 



265. Titrinella pcrparra. Nov. sp. 



Shell subdiscoidal: white: with a very prominent acute 

 spiral keel on each side of the periphery of the last whorl, and 

 a less prominent one around the umbilicus; with transverse 



