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 ventbicosa. 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 

 iente arcuata; cardine valde debili. Long. 17; alt. 9 ; lat. <s 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 hyalina. 



Lyoxsia (Pandorina) fi.auelj.ata. T. oblongo-ovata, nasica, 

 ventricosa. tennis, opalina, straminea, exilissime striata; umbonibus ad 

 trieritem anteriorem sitis ; extremitate antica arete rotundata; mar- 

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

 continuo arcuata usque ad angulum superiorem: cardo debilis; sulco 

 ligamentali angusto; pagina interiori opalina. Long. 17; alt. 1"; 

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



Very 'lose upon P. arenosa Moll., but the stria; are more numerous 

 and delicate. 



N; i.ka adlxca. T. minuta, alba, globosa, ovato-triangularis, 

 concentrice lirata; umbonibus fere medianis, elevatis, tumidis; extre- 

 mitate antic;: globosa; extrem. postica subito augustatii, triangulari 

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

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

 \V. S. 



Theora ltjbbica. T. parva, fragilis, pellucida, oitida, straminea, 

 ovato-crescentica, ventricosa, postice. compressa; umbonibus nonnihil 

 antemedianis; extremitate antica acute rotundata: extrem. postica 

 acuta: margine ventrali bene arcuata; cost a interna ex umbonibus 

 oblique antrorsum products. Long. II : alt. 7; lat. 3 millim. In- 

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



TiiKin: \ m tida. T. tenuis, fragilis, nitida, lucida, alba, clongato- 

 ovata, subfalcata, epidermide straminea induta; umbonibus anteme- 

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

 subadscendente ; margine dorsah postica declivi; margine ventrali 

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

 Long. M: 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; 



