353 



angular sides, deltidia rather large, separate ; mesial ridge very 

 slight ; ventral valve nearly orbicular ; internal appendage large, 

 z ths the length of the shell, formed as in T. Calif or nica ; margin 

 °f the valves entire. 



In the British Museum and in Mr. Metcalfe's Collection. 



20. Terebratula Uva (pi. lxx. f. 53-55.) Brod. Zool. Proc, 

 1833, p. 124-. 



Testa oblonga, gibbosa, glabra, subdiaphana, pallescente ; valvis 

 inrequalibus ; linea marginah ex umbonem ascendente, demimi 

 subtiexuosa ; valva dorsali postice subelongata, apice reflexo, trun- 

 cato, foramine magno, integro, perobliquo, margine crasso; area, 

 cardinali inconspicua, rotundata ; deltidiis parvis, coalescentibus, 

 concavis ; carina mediana nulla ; valva ventrali ovato-oblonga, sulco 

 mediano nullo ; ossiculo interno parvo, radiis binis, ex cardinem 

 extensis, ad apices expansis efformato ; margine valvarum integro. 



Shell oblong, gibbous, smooth, slightly diaphanous, pale in 

 colour ; valves unequal ; marginal line ascending from the apex, 

 then somewhat fiexuous ; dorsal valve posteriorly lengthened, 

 with a reflected, truncated apex; perforation large, entire, 

 very oblique, with a tliickened margin; cardinal area indistinct, 

 rounded ; deltidia small, united, concave ; ventral valve ovato- 

 oblong ; internal appendage formed of two rays setting off from 

 the hinge and expanded at the ends ; margin of the valves entire. 

 This species is destitute of mesial ridge and furrow. 



Froin the Gulf of Tehuantepec; in Mr. Cuming's Collection. 

 The punctulation in this species is much coarser than in T. vitrea. 



21. Teuebratula. vitrea (pi. lxx. f. 56-59.) Lam. 



Testa, rotundato-ovata, ventricosa, subdiaphana, lajvissima, albi- 

 cante ; valvis subEequalibus, linea marginali rectiuscula ; valva. 

 dorsali postice rotundato-subacuminata, recurva ; foramine parvo, 

 integro, snbobliquo, margine crasso ; area cardinali inconspicua, 

 rotundata ; deltidiis inconspicuis, coalescentibus ; carina mediana 

 nulla; valva ventrali subcirculari, antice rotundato-subtruncata, 

 sulco mediano nullo ; ossiculo interno parvo, i longitudinis testse, 

 antice arcuato, fornicato ; margine valvarum integerrimo. 



Shell of a rounded ovate form, ventricose, slightly diaphanous, 

 very smooth, whitish horn colour, valves nearly equal and marginal 

 line nearly straight ; dorsal valve rounded and slightly acuminated 

 behind, recurved; perforation small, entire, rather oblique, with a 

 t hickened margin ; cardinal area indistinct, rounded, with united 

 indistinct deltidia ; ventral valve nearly circular, slightly truncated 



