S02 - 



":cL. V ", "^lie lar-est loft vclve Ik ' -^he foil ^: ■• : 



lit., 18 !:]iii., alt,, >-0,5 nr...; diani., 10 up. i'he sciilptT-U-e oi' z.c 

 attache- , in this case, the left, vrlve is, as usual, irren:- 



;il9.r, Ihe raclial scales, vrhich rarelj- vre of sr,oh ire aG ^~ 



be ternie'' spiiies, are often partially or completerlj obsolete, out 

 the peculiar, irregularis? radial, int errupte^l , pxzstular sculpture 

 Is usxially persistent. Gn ri.;rht valves, althouo-h the ornsmertati ->r. 

 is rela"tivel;,' constant, the nunber of concentric lamellae, L.r.d there- 

 Tore the spacing, varies, as well as the relative coarseness of 

 the creniil atioiis , ~hich in a fe?/ exceptional casps are a.rranged in 

 regular radial series. 



The nepionic shell is preserve'! on a few of the valves; it is 

 minute, subquadrate, ":ith the umbo at the anterior enn, snd sculp- 

 tured with sis or seven distant, regularly spaced, sharol;; raised 

 and slightly recurved ooncentrie lamellae with intervening obscure, 

 fine concetitric striae. 



The small size, "vermicular" and radially scabrous or spiny s 

 ■Gulpture of the attache'', left valve and the numerous finely crenii- 

 late*^ lamellae O"^ ^"'^'^ i-- -v-f: -r^i vo r.-re characteris-^i '^ -^r-t-^-'es of 

 oecies. ihe Jhipolan J_. draoonis Dall (l) i£ lar;;-er and 



J-U^ . - . , • , • , ' • . • - • 



attached by the right valve; the sc \ e :<f -■, com- 



