no smith: description of a new species of gomphina. 



curvatus, ventralis late arcuatus ; umbones mediocriter prominentes, 

 fere contigui, postmediani ; valvae concentrice fortiter striatae, baud 

 lunulatae intus albae, in medio rufo plus minus saturatae, ad marginem 

 laeves ; cicatrix antica ovalis, posterior brevior, magis rotundata ; 

 sinus pallii parvus, minime profundus. 



Longit. i6 millim., alt. 13, diam 8. 

 Both of the examples of this species which I have examined, exhibit 

 two brown rays, one down the middle of the valves and the other 

 posterior to it, the rest of the surface being marked with irregular wavy 

 or zigzag lines, and they are slightly reddish towards the umbones. 



The species is at once separable from Gomphina iindulosa, 

 Lamarck*, by the difference of form and the different position of the 

 beaks and the relative difference in the extent of the anterior and 

 posterior ends. In G. undulosa the beaks are slightly antemedian, 

 whereas in the present species they are decidedly postmedian. The 

 extent of the valves in front of and behind the umbones, is con- 

 sequently reversed in the two forms. The style of colouration, the 

 dentition of the hinge and the character of the scars and pallial line 

 are alike in both. G. moerchi of Angasf is a more convex and 

 triangular shell and subrostrate posteriorly. This subrostration, 

 however, is only noticeable in the adult form, for young examples 

 are quite obtuse behind. The locality of 6^. moerchi was unknown at 

 the time it was described, but examples, received from the late M. 

 Robillard, show that it occurs at the Mauritius. G. undtdosa has 

 been recorded from the same locality. ft 



* See Pfeiffer, Conch. Cab., ed. 2, Veneracea, p. 1&6, pi. xxiii, fig 3; Reeve, Concli. Icon., 



vol. xiv, Venus, pi. xxv, figs. i25a — b. 

 t Proc. Zool. Soc. London, 1872, p. 611, pl.xlii, fig. 7. 

 ft Martens in Moebius's Beitiage zur Meeresfauna der Insel Mauritius und des Seychellen — 



MoUusken, p. 326. 



