162 



undulis concentricis, circ. 20 ad margines haud protractis ornata; 

 (valvfi sinistra, ignota) : cardo debilis ; dentibus elongatis. Long. 8 ; 

 alt. 7 ; lat. 3 millim. Inhabits Kagosima Bay. W. S. 



Allied to M. brevis, which is larger and more finely ribbed. There 

 is one in the Cuming Coll. much like it. 



Lyonsia ventricosa. T. ovato-falcata, tenuis, fragilis, lucida, 

 straminea, ventricosa, concentrice exiliter striata et rugis hispidis 

 radiata ; umbonibus satis antemedianis ; extrem. antica rotundata ; 

 extrem. postica angustante ad apicem truncata ; margine ventrali 

 lente arcuata ; cardine valde debili. Long. 1 7 ; alt. 9 ; lat. 8 millim. 

 Inhabits Hakodadi Bay, 2-6 fathoms, sandy mud. W. S. 



Its shorter and less slender form, and its color, distinguish it from 

 L. Norvegica and liyalina. 



Lyonsia (Pandorina) flabellata. T. oblongo-ovata, nasica, 

 ventricosa, tenuis, opalina, straminea, exilissime striata ; umbonibus ad 

 trientem anteriorem sitis ; extremitate antica arete rotundata ; mar- 

 gine dorsali postica recta ; margine ventrali una cum extrem. postica 

 continue- arcuata usque ad angulum superiorem : cardo debilis ; sulco 

 liganientali angusto ; pagina interiori opalina. Long. 17; alt. 10; 

 lat. 6 millim. Inhabits Arctic Ocean. W. S. f' 



Very close upon P. arenosa Moll., but the stria? are more numerous 

 and delicate. 



Nevera adunca. T. minuta, alba, globosa, ovato-triangularis, 

 concentrice lirata ; umbonibus 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 Bay, sandy mud, 12-15 fathoms. 

 W. S. 



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

 ovato-crescentica, ventricosa, postice compressa ; umbonibus nonnihil 

 antemedianis ; extremitate antica acute rotundata : extrem. postica 

 acuta ; margine ventrali bene arcuata ; costa interna ex umbonibus 

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

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



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

 ovata, subfalcata, epidermide straminea induta ; umbonibus anteme- 

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

 subadscendente ; 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, liyalina, equila- 

 teralis, utroque extremitate rotundata, tenuissime radiatim striata; 



