1(14 



what crystalline coat, which extends beyond the first at the margin. 

 This latter crystalline or tessellated structure is very clearly exhibited, 

 and probably obtains in all the species. The variation in outline 

 from the original type was so great that I had named these specimens 

 P. sagrinata. 



Corbela vi'.xrsTA. T. parva, solida, albida (vel rosacea) ovato- 

 triangularis, admodum compressa, suba?quivalvis, concentrice arata, 

 liris intereurrentibus rotundatis; umbonibus medianis antice excavatis ; 

 extremitate antica rotundata; extrem. postica altiori et latiori. vix 

 truncata ; margine dorsali arcuata ; declivitate umbonali carinata. 

 Long. 10; alt. 7; lat. 4 millim. Inhabits Ilakodadi Bay, in shelly 

 sand, 5-8 fathoms. W. S. 



Some smaller specimens are proportionally shorter, and have the 

 grooves much more distant, and if seen alone, would be considered a 

 different species. 



Cokbula (Azara) rtjstica. T. parva, ovato-trigonalis, solida, 

 lnevis, epidermide tenui rufescente induta; umbonibus submedianis 

 inconspicuis, erosis; valvae majoris marginibus dorsalibus arcuatis, 

 declivibus ; extremitate antica rotundata; extrem. postica obtuse 

 truncata; valva altera graciliori, penitus inclusa ; declivitate umbonali 

 obtuse angulata; cardine debili ; cavositate cretacea. Long. 15; alt. 

 y ; lat. 5 millim. Inhabits Whampoa. W. S. 



Some of the specimens are much more triangular than others. 



Solecurtus abbreviated. T. tenuis, elongato-rhoinboidea com- 

 pressa, striis incrementi insculpta, sulco radiante obliquo albido-mar- 

 ginato excepto ; umbonibus minimis medianis: margine dorsali antica 

 rect;i, declivi; extremitate antica oblique retrorsum truncata; angulo 

 dorsali postico declivi; angulo postico ventrali rotundato; margine 

 ventrali incurvata. Long. 45 ; lat. 10 ; alt. 20 millim. Inhabits Hong 

 Kong. W. S. 



Soi.ixurtus strigosus. T. tenuis, compressa, transverse ob- 

 Longa, concentrice striata; epidermide flavo-viridi, postice verticaliter 

 rugosa, ; umbonibus minimis ad quadrantem anteriorem sitis; margine 

 dorsali antica declivi; extrem. antica oblique retrorsum truncata; 

 angulo superiori acuto; extremitate postica acute rotundata ; margine 

 ventrali incurvata ; declivitate umbonali obtuse angulata. Long. 50 ; 

 alt. 7 ; lat. 7 millim. Inhabits Whampoa. W. S. 



Soeecurtus debilis. T. parva, tenuis, lucida, alba, oblongo- 

 ovalis, compressa, concentrice striolata, striis in medio obliquis, epider- 

 mide llavescente tenuissima hie illic induta; umbonibus prope trientem 

 longitudinis sitis. postice excavatis; extrem. antica rotundata . ; extrem. 

 postici acutiori ; margine dorsali postica demum declivi ; margine ven- 

 trali quantulum concava. Long. 25; lat . r> ; alt. 7 millim. Inhabits 

 Port Lloyd, and Loo Choo Island. < '<ij>l. Rodgers. 



