347 



ad utrumque latus aculeifero, deinde ad medium valvae decurrentc, 

 et amenta dua lateralia, dcmi\m amentum superum magnum re- 

 flexum efformante ; margine valvarum crenulato. 



Shell of a suborbicular trapezoidal form, rather gibbous, whitish, 

 valves unequal, radiately ridged; marginal line flexuous; dorsal valve 

 slightly acuminated posteriorly, reflected, truncated, with a broad 

 obtuse central ridge, and a rather large, but not complete perfora- 

 tion ; cardinal area large, broad, rather flattened, with small trian- 

 gular deltidia; ventral valve rather trigonal, with a rather acute 

 apex, its posterior margins inclined laterally ; with a broad, not 

 very distinct longitudinal central groove ; internal appendage large, 

 f-ths the length of the valve, with a sharp point standing out from 

 the posterior part, then running down to the centre of the valve, 

 and forming two lateral loops, which turn upwards and unite after 

 forming a large superior loop ; margin of the valves crenulated. 



From the Straits of Magalhaens : common. 



10. Tekebratula Chilensis (pi. lxviii. f. 18, 19). Brod. Zool. 

 Proc, Nov. 1833, p. 134. 



Testa, suborbiculari, subtranversa, subgibba, pallescente, valvis 

 subsequaliter convexis, radiatim bratis, bris obtusis, baud promi- 

 nentibus ; linea marginali rectiuscula, antice sinuata ; valva dorsali 

 postice obtusa, lateribus declivibus, carina mediana lata, obtusissima, 

 foramine magno, subintegro ; area cardinab magna, lata, planulata, 

 deltidiis mediocribus, trigonalibus ; valva ventrali transversim 

 ovata, subplanulata, sulco mediano lato, perspicuo ; ossiculo interno 

 magno, |- testae longitudinis, amenta ut in T. dorsatd efformante ; 

 margine valvarum obsolete subcrenulato. 



Shell suborbicular, somewhat transverse and slightly gibbous, 

 of a pale colour ; valves nearly equally convex, with numerous ob- 

 tuse scarcely prominent ridges ; marginal line nearly straight, 

 sinuated in front ; dorsal valve obtuse posteriorly, with inclined 

 sides and a broad, very obtuse longitudinal central keel, perforation 

 large, nearly entire, cardinal area large, broad and flattened, delti- 

 dia of moderate size, triangular ; ventral valve transversely ovate, 

 rather flattened, Math a broad, distinct central groove ; internal 

 appendage large, f-ths the length of the valve, forming loops as in 

 T. dorsata ; margin of the valve rather crenulated. 



Prom the Bay of Valparaiso ; Cuming. 



11. Teuebeatula flexuosa (pi. lxix. f. 23, 24.) King. Zool. 

 Joiirn., vol. v, p. 337. 



Testa subtetragona, rotundata, subgibba, fuscescente pallida ; 



