

3RyOIiIA PlI^A n. sp. 



Desoriptlon .- oliell of ne di-D.m oL^.u, uhin, o ibtrexislucent, 

 elongate, ^1 inflated, ineqxiilateral ; more oroduce" lore 



convpxlj' ronndecl anteriorly; a::tero-dorsa3. 'n strs i'-'-ht , slop- 



iij- t.'xi '..l^ , .L'ot!.nding broadly into the carve c 'ior c "• 



postero-dorsal raarprin shorter, conve:?:, curving f!ore j into the 



roimded posterior evA; hase straipht; nmho 1 ' , _, 'laoe^ he- 



'!~in'^, the meditai ]ix>± i-j- :>l^ al; lue icm v eiv. xc-.l ;jur l ^ e s:iliell 



very slightly constricted; sitrfaoe hearing vr concentric s 



striae; rieht valve vath a sinf^le cardinal and :. ';al lam- 



inae. 



Dir:ensions .- length, 8 mm.; alt., " .; adiam., 1.5 rara. 



?ien)ar":b .- A single rip-ht valve of this e^xeies h.?s j-o^^eare""'. 

 in the collections. It is readily disb- ' j':- _. ';. '\c.'1l^ ;:, 



hy its much larger size and less ineqfeilateral outliiie. The riocexie 

 (Duplint and Pliocene f '.Vaccarna'.? and Caloos: ' _. carolinonsis 



Jail (1) is larger, less elongated and less irjflaL"ed. 



(l^. Tra-ns . 7/'agner "^ree Inst ^ Sci., ■^hiladel->-)hia, vol. ^^ , •'-'t. 

 5, ^. 111-5, pi. 44, a?s. 5, £2, lOCO, 



Oec'irrenoe.- Iov;er Miocene : Bowden beds, "^o^vden, J'arnaica, 



