354 



anteriorly ; internal appendage small, j-th the length of the shall, 

 anteriorly arched and vaulted ; margin of the valves entire : mesial 

 ridge and furrow none. 



From the Mediterranean ; in Mr. Cuming's and other Collec- 

 tions. 



22. Terebratu la Cranium (pi. lxx. f. 60-62). Mull. 



Testa ovata, antice subtruncata, postice paulisper acuminata, 

 gibbosa, pallescente, subhyalina ; valvis sequaliter convexis ; linea 

 marginali flexuosa, antice subsinuata; valva dorsali postice sub- 

 producta, subrecurva, oblique truncata; foramine magno, baud 

 integro ; area cardinali inconpicua, rotundata ; deltidiis parvis, 

 linearibus, distinctis ; valva ventrali planiuscula, antice subangu- 

 lata ; ossiculo interim magno, f longitudinis testae, amentis binis 

 lateralibus, ad utrumque latus uno, deraurn amento magno supero 

 efformante ; margine valvarum integerrimo. 



Shell ovate, anteriorly subtruncate, posteriorly slightly acumi- 

 nated, gibbous, of a pale colour, somewhat diaphanous; valves 

 equally convex, marginal line flexuous, slightly sinuated in front ; 

 dorsal valve somewhat produced posteriorly, slightly recurved, 

 and obliquely truncated ; perforation large, incomplete j cardinal 

 area indistinct, rounded, with small linear, separate deltidia; 

 ventral valve slightly flattened, and somewhat angular in front ; 

 internal appendage large, f rds the length of the valve, forming two 

 lateral loops, one on each side, and then uniting to form one very 

 large upper loop ; margin of the valves quite entire. 



From the coast of Norway and the North Seas ; in Mr. Cuming's 

 and other Collections. This species resembles T. vitrea in general 

 appearance, it may however easily be distinguished by its large 

 foramen which is not entire ; as well as by its extended internal 

 appendage. 



23. Terebratula truncata (pi. lxxi. f. 64-67.) Lam. 



Testa transversim suborbiculari, depressa, latere cardinis trun- 

 cato, rectiusculo, pallescente, valvis subsequalibus, radiatim con- 

 cinne striatis, linea marginali subirregulari, rectiuscula, antice sub- 

 sinuata; valva dorsali postice truncata, emarginata, foramine magno, 

 haud integro, area cardinali elongato-trigonali, planulata ; deltidiis 

 minutis, inconspicuis ; carina mediana parva ; valva ventrali sub- 

 planulata, postice rectiuscula, emarginatione mediana parva ; sulco 

 mediano latiusculo, subinconspicuo ; ossiculo interno valde com- 

 plicate, nonnunquam vario; facie interna radiatim granifera, 

 granulis seriatim confertis, parvis ; margine valvarum integro. 



