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curvata; fastigio antero-dorsali elevato ; umbonibus ad quadrantem an- 



teriorem ventricosis ; areis terminalibus concinne radiato-striatis ; area 

 mediana inornata. Long. 5 ; alt. 2 millim. Inhabits Kagosima. W. S. 



M. qtjadrula. T. subquadrata, marginibus parallelis, ventrali 

 vix incurvata ; extreniitate antica rotundata ; extrern. postica oblique 

 truncata ; apicibus fere terminalibus ; deelivitate postero-dorsali 

 modice exposito ; areis terminalibus radiato-striatis ; area mediana 

 inornata. Long. 10 ; alt. 5 millim. Inhabits Kagosima. W. S. 



The two latter descriptions are taken from two single valves, quite 

 unusual in form ; perhaps accidentally distorted. 



Mytiltjs coruscus. T. pyriformis, margine ligamentali vix 

 arcuata ; marg. postero-ventrali angulata, late truncata ; regione 

 byssali lente incurvata ; facie antica lata angulo submarginali limitata, ; 

 epidermide crassa picea antiee castaneu ; margine interiori nigra : 

 cavositas ad cicatrices ex viridi iricolor argillaceo versus apicem 

 mutata. Long. 65 ; alt. 38 ; lat. 25 milUm. Inhabits Hakodadi 

 Bay, common on rocks between tide marks. W. S. . 



A very symmetrical species, quite remarkable for the brilliancy of 

 its interior. 



Mytiltjs mtjtabilis. T. elongata, margine byssali fere recta ; 

 marg. dorsali lente omnino arcuata in marginem ventralom continua ; 

 umbonibus pallidis, acutis, plerumque erosis ; valvis versus apicem 

 radiatim sulcatis, sulcis sensim evanescentibus, alibi glabris, epidermide 

 castanea nitida indutis; facie ventrab concinne striata : cavositas 

 hepatiea. Long. 30; alt. 16; lat. 12 milUm. Inhabits Kagosima 

 Bay. W. S. 



Like M. trossulus or small specimens of M. edulis in form, but much 

 more elongated. The diverging furrows are quite coarse and obvious 

 in some specimens, and in others obsolete ; the fine striation in the 

 neighborhood of the byssus may always be seen. 



Septifer ftjrcillata. T. parvula, pyriformis; margine liga- 

 mentali angulata, compressa ; deelivitate umbonali elevata ; facie 

 Hgamentali lata, margine recta ; sulcis quadratis divergentibus con- 

 cinne clathratis insculpta, sulco mediano et sulco subventrali majori- 

 bus, ex quibus sulci versus marginem recurvati exoriuntur. Long. 8 ; 

 lat. et alt. 4 millim. Inhabits China Seas. W. S. 



A somewhat worn valve furnishes the above description, which I 

 venture to give because the sculpture is so peculiar. It has the form 

 of S. Cumingii, but a mujh coarser sculpture. 



Pecten L.ETUS. T. rotundato-ovata, convexiuscula, vivide rufa ; 



auricula parva fere rectangulari ; a. altera duplo longiori, acutangu- 



lari, extremitate arcuata ; sinu byssali magno ; valva3 integrse costis 



10-12 majoribus laminas remotas erectas fornicatas gerentibus, 3-4 



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