352 



both sides ; ventral valve somewhat pentagonal, narrow posteriorly, 

 broad in the middle, with rounded angles, and slightly truncated 

 in front ; mesial groove broad and distinct ; internal appendage as 

 in T. dorsata ; margin of the valves entire. 



Trom the Moluccas ; in Mr. Cuming's Collection and in the 

 British Museum. 



18. Terebeatula Californica (pi. Ixx. f. 50-52.) Kust. 



Testa suborbiculari, postice subacuminata, gibbosa, fuscescente, 

 valvis subaequalibus, glabris ; linea marginali ex umbonem ascen- 

 dente, demum rectiuscula, antice et mediane obsoletissime siimata : 

 valva dorsaH subrostrata, apice brevi, subacimiinato, reflexo ; fora- 

 mine parvo, integro ; area cardinali latiuscula, marginibus obtuse 

 anguliferis ; deltidiis oblongis, trigonalibus, coalescentibus ; ca- 

 rina mediana nulla; valva ventrali orbiculari, sulco mediano 

 nullo ; ossiculo interno magno, § testes longitudinis, fere ut in T. 

 dorsata efformato ; margine valvarmn integro. 



Shell nearly orbicular, slightly acuminated posteriorly, gibbous, 

 light brown ; valves nearly equal, smooth, marginal Hne ascending 

 from the apex and then straight, anteriorly and in the centre very 

 obsoletely sinuated; dorsal valve slightly beaked, apex short, 

 slightly acuminated, reflected ; perforation small, entire ; cardinal 

 area rather broad, its edges obtusely angidar ; deltidia oblong, tri- 

 angular and united ; mesial ridge none ; ventral valve orbicular, 

 without any mesial furrow ; internal appendages large, -|ds the 

 length of the shell, formed as in T. dorsata ; margin of the valves 

 entire. 



Abounds on the Coasts of California ; in Mr. Cuming's and 

 other Collections. This is the largest recent species known. 



19. Terebratula dilatata (pi. Ixx. f. 48. 49.) Lam. T. 

 Gaudichaudi, De Blainv. 



Testa suborbiculari, tenui, glabra, fulvescente ; valvis insequali- 

 bus, Knea marginali flexuosa ; valva dorsali postice subacuminata, 

 reflexa, obtusa ; foramine magno, baud integro ; area cardinali 

 majuscula, planulata, lateribus obtuse angulatis, deltidiis majus- 

 culis discretis ; carina dorsali obsoletissima ; valva ventrali sub- 

 orbiculari ; ossiculo interno magno, f longitudinis testge, ut in T. 

 Calif ornicd efformato ; margine valvarum integro. 



Shell nearly orbicular, thin, smooth, of a pale broAvnish colour ; 

 valves unequal ; marginal line flexuous ; dorsal valve slightly acu- 

 minated posteriorly, reflected, obtuse ; with a large incomplete 

 perforation ; cardinal area rather large, flattened, w ith obtusely 



