24: 



Xe.era aduxca. T. minuta, alba, globosa, OTato-triangularls, 

 concentrice lirata ; umbonibiis fere medianis, elevatis, tumidis : extre- 

 mitate antica globosa ; extrem. postica subito augustata, triangulari 

 acuta, deflecta ; margine ventrali concave arcuata. Long. 5 ; lat. et 

 alt. 4 millim. Inhabits Kagosima Bar, sandy mud, 12-15 fathoms. 



^v. s. 



Theora lubrica. T. parva, fragilis, pellucida, nitida, straminea, 

 ovato-crescentica, rentricosa, postice compressa ; umbonibus nonnihil 

 antemedianis ; extremitate antica acute rotundata : extrem. postica 

 acuta ; margine ventrali bene arcuata ; costa interna ex umbonibus 

 oblique antrorsum producta. Long. 1 1 ; alt. 7 ; lat. 3 millim. In- 

 habits Hakodadi Bay, very common in mud, 6 fathoms. W. S. 



Theora xitida. T. tenuis, fragilis, nitida, lucida, alba, elongato- 

 ovata, subfalcata, epidermide straminea induta ; umbonibus anteme- 

 dianis ; extremitate antica rotundata ; extrem. postica acuta, compressa, 

 subadscendeute ; margine dorsali postica declivi ; margine ventrali 

 arcuata : cavositas porcellana, rosaceo tincta, radiatim tenuiter striata. 

 Long. 14 ; alt. 8 ; lat. 5 millim. Inhabits Hong Kong harbor. 



Possibly T. fragilis Hinds, but seems smaller and more slender. 



Theora obtusa. T. parvula, ovalis, tenuissima, hyalina. equila- 

 teralis, utroque extremitate rotundata, tenuissime radiatim striata ; 

 costa interna gracili, elongata, lactea. Long. 10; alt. 6; lat. 3 

 millim. 



Only one valve was obtained, evidently more equilateral, thin, and 

 obtuse posteriorly than any described species. 



Saxicava flaccida. T. tenuis, subnacrea, multiformis plenmique 

 subquadrata varie distorta, concentrice undulata, epidermide tenui 

 ochracea rugosa induta ; umbonibus terminalibus, tumidis ; declivitate 

 post-umbonali carinata interdum spinulosa : cavositas subnacrea ; 

 cardinis dente valido elongato, uncinato. Long. 20; alt. 13: lat. 10 

 millim. Inhabits Hong Kong and Simon's Bay. W. S. 



The strong cardinal tooth and the semi-pearly structure are al- 

 together unusual for this genus. It would come under Hiatella or 

 Rhomboides, which are now regarded as variations of Saxicava. I 

 cannot distinctly make out a paUial impression. The animal has a bys- 

 sus. Perhaps these shells have been confounded with Sax. rugosa, 

 which is said to come from Cape of Good Hope, Cliina, &»•. I am 

 by no means certain that the shells from the two localities which 

 I have had under inspection are the same. Those from thu latter 

 locality are certainly much the smallest. 



Cryptomya truncata. T. tenuis, alba, rotundato-ovata. postice 

 oblique truncata ; umbonibus submedianis, parvis ; valva (dextra) 

 tumida, fastigio acuto ab umbone ad angulum postero-ventralem 



