239 



sulcata (limidialis; areis, antica oblique divisa, partc postica 

 dorsali conccntricc lamellosa, lamellis squamiiliferis, parte 

 aulica veulrali teniiiorc, inflala, radialim obsoletc costel- 

 lala; postica longitudiualiter sulcata; margine dorsali autica 

 concavo-reflexa, musculum recipiente, epidermide oblecta; 

 cpidermidc postice iu vesiculas quatuor, undique duas, de- 

 curreutc, deinde in tubulum calcaicum ad cxtremam parlem 

 conspicuum. 



Var. tcsfa parva, marglne dorsali aulica inflato-reflexa. 



Long. 1- poll,, lat. 0-3 poll., alt. 0-3 poll. 



Juvenes tubulo aliisque et acccssoriis partibus carent. 



Lcglt n. Cumlng in lapidibus, ad montem Christi Co- 

 lumbiae occidcnlalls. 



Proceedlngs. 1834. p. 71. 



J. Pholas curta G. B. Sowerby. 



Ph. testa ovali, postlce acuminata, antice rotundata; 

 valvis fascla trausverslm sulcata dlmidlatis; arels, autlca 

 obilque dlvisa, parte postica dorsali longltudinaliter striata 

 ct radiatim corrugata, parte autlca ventrali tenuiore, sub- 

 inflata; postica concentrlce striaia; valva accessorla solita- 

 ria, dorsali, antica, utraque extrcmltate subacuminata, me- 

 dio coarctata; marglnlbus ventrali dorsalique epldermide 

 corneo-testacea obtectis, parte dorsali poslice furcata. 



Long. 0-6 poll., lat. 03 poll,. alt. 035 poll. 



Lcglt n. Cumlug in saxls molllbus ad Ilttora Colum- 

 blac occidentalls (Islc of Lions, Proviuce of Veragua). 



Procecdings. 1834. p. 71. 



). P li o 1 a s c o r ii e a G. B. Sowerhy. 



Ph. Icsta oblonga, tcnul, antlce roluudata, postice ob- 

 tusa; cpldcrmldc tcnui cornea indiita; valvis fascia diniidia- 

 tls; aroa aiilica obliquc divisa, parlc posllca dorsall rugo- 

 slusciila, partc antica lacvl; arca posllca majore, laevigata; 

 valvis acccssoriis ti-ibus, antica dorsali rotuudata, postice 

 subemarginata, antice subacuminata; hiatu postico magno. 



Long. 0-9 poll., lat. 05 poll., alt. 05 poll. 



