orb 111 a h eterop-ena Ou■:^^37, ".ro-un arr^ Pilsbry, 191], Proc. Acad. 

 -at. 3ci., "^hila^'olphia, vol. G5, p. ?7.1. 



Descri-otion »- "^his form is very clo-oe to 2* vieta . n-f-- 

 differs from it in hL^vinr ' beaks narrov7er, less elevate^., and 

 less prominent, and the posterior -oart of the shell more pro- 

 duced. Ion. 9.5, alt. 8, diara. 5 mm." f Dall, 1898). 



T;;pe looalit.y .- 3owden, Jamaica. 



Hight valve of nteditira size, high, decidely inflated, sub- 

 equilateral to moderately ineo ■ dlateral, clir-htly more produced 

 posteriorly; dorsal marrins subequal, both ooncave, roxmded anter- 

 iorly below, posteriorly trujicatea below, base gently arcuate; 

 i-mbones tumid, high, stronrl: incruve' and moderately to deci^^'er!- 

 ly prosogyrate, subcentral in position; near th'. posterior mer-in 



an oiaseure carina present, lollov/ed anteriorly by a stronger, 

 roadly rounded carina, the area betr/een the tv:o flattened or 

 slightly depressed; surface sculptured v/ith concentric rof.ae of 

 medium width; left valve small, elonprate subovate, well- inflated, 

 moderately i-„ Hate al; roimded anteriorly, trrincatod r)oster- 

 iorly; ant ero-dor sal margin si iP'htly concave, postero-dorsal 

 slip-htly loni?er and straight; umbones tamld, moderately hip-h, 

 ■olaced before the median vertical; posterior carina lo\'.', obscure; 

 sculpture of obscure, fine concentric rugae, suppressed over much 

 or all of the sr'jrfa -e and about ten to tv7elve very narrow radi- 

 als, the posterior slope v,-ithout rrdial sc uJ.pt itr e ; the marrins 



