171 



subcirculari ; extrem. postica acutiori, obliqua ; ligamento conspicuo : 

 cavositas ex albo viridans, costa ab umbone usque ad cieatricem 

 anteriorem munita ; margine iuteriori simplici ; dente laterali antico 

 minimo vel obsolete Long. 30; alt. 27; lat. 15 millim. Inhabits 

 Hakodadi Bay, in sandy mud, 8 fath. W. S. 



It has the general aspect of Astarte, with its thick, dark epidermis, 

 but has the hinge of Mysia, subgen. Felania. 



Mysia dolabrata. T. parva, compressa, symmetrica, rotundato- 

 quadrata, flavescens, glabra ; umbonibus medianis, parvis, acutis ; 

 costa interna intra-umbonali exili, postice submarginali. Long. 10 ; 

 alt. 10 ; lat. 4 millim. Inhabits Simon's Bay, Cape Good Hope. 



w. s. 



Generally resembles Felania Senegalensis. 



Mysia figlina. T. oblique rotundata, lenticularis, nitida, con- 

 centrice striolata, pallide argillacea ; umbonibus acutis vix antemedi- 

 anis ; disco intus calcareo ; dentibus cardinalibus validis ; costa intra- 

 umbonali obliqua, satis conspicua. Long. 18; alt. 16; lat. 6 millim. 

 Dredged off the east coast of Japan, lat. 37°, in coarse, black sand, 

 20 fathoms. W. S. 



Has a peculiar argillaceous look which may serve to distinguish it 

 from other species. 31. dolabrata scai'cely differs except in polish, 

 size, and obliquity of beaks. 



Mysia abbrevtata. T. tenuis, fragilis, straminea, glabra, subglo- 

 bosa, postice valde truncata, superne compressa ; declivitate umbonali 

 angulata ; antice rotundata ; umbonibus medianis, tumidis, acutis ; 

 lineis incrementi conspicuis : cavositas cretacea, citrina. Long. 20 ; 

 alt. 1 7 ; lat. 1 2" millim. Inhabits Hong Kong harbor. W. S. 



Mysia obliqua. T. parvula, oblique rotundato-ovata, lenticularis, 

 flavescens, zonis incrementi rai'is ornata ; umbonibus antemedianis ; 

 regione postica latiori, rotundata ; margine ventrali oblique arcuata ; 

 costa interna umbonali tenuissima ; cardine debihsshno. Long. 8 ; 

 alt. 7 ; lat. 3.5 millim. Inhabits Loo Choo. W. S. 



Has no very marked characters, but in general is like a small M. 

 gldbularis Lk. It is more globose than M. fglina. It is possibly a 

 very small specimen of Diplodonta Koreensis Ad. and Rv. 



Lepton firmatum. T. subtrigona, planata, lactea, subdiaphana, 

 glabra ; umbonibus medianis, baud eminentibus ; margine ventrali 

 fere recta ; pagina interiore subrugosa ; cicatricibus subrotundis ; denti- 

 bus curtis, validis. Long. 5 -f- ; lat. 2 -\- ; alt. 4 milhm. Inhabits sand 

 at low water, Simon's Bay. W. S. 



In shape like L. squamosum, but distinguished by its short, stout 

 teeth. The rugosities are probably caused by a perforating parasite. 



Lepton concentricum. T. ovato-triangularis, subplana, con- 

 centrice concinne Urata (liris acutis), epidermide subrugosa marginem 



