Zoological Society. 299 



convexo, ultimo | longitudinis cBquante ; columeUd vix' arcuatd, 

 recedente ; aperturd obliqud, ovali ; peristomate simptice, mar- 

 gine deoctro superne subincurvato, turn strictiusculo. 



Long. 4f, diam. 3 mill.; ap. Z\ mill, longa, 2 lata. 



Hab. Ceara, in America meridionali. 



1 1. SucciNEA RUBicuNDA, Pfr. S. testd ovatd, temd, striatufd, 

 sub lente obsolete granulosd, diaphand, parum nitidd, luteo- 

 rubescente ; spird brevi, sanguined, subpapillatd ; anfractibus 

 2\ convexis, idtimo injlato ; columelld callosd, substrictd re- 

 cedente ; aperturd parum obliqud, angulato-ovali, intus niti- 

 dissimd ; peristomate simplice, margine dextro regulariter ar- 

 cuato. 



Long. 14, diam. 8, alt. 5 mill.; ap. 10^ mill, longa, medio 6 lata. 

 Hab. in insula Masafuera (Cuming). 



12. SucciNEA SOLTDULA, Pfr. S. testd dspresse ovatd, soUduld, 

 longitudinaliter subplicatd, sub lente tninutissitne granulatd, vix 

 diaphand, parum nitiduld, fulvd ; spird brevi, scalari, apice pa- 

 pillatd, rubicundd ; anfractibus 2\ convexis, ultimo injlato, |- 

 longitudinis oequante ; columelld substricte descendente, callosd; 

 aperturd oblongd, intus submargaritaced ; peristomate submar- 

 ginato, marginibus callo tenui junctis, dextro superne arcuato, 

 turn strictiore. 



Long. 12, diam. 7, alt. 5| mill. ; ap. 8^ mill, longa, 5 lata. 

 Locality unknown. 



The form of this shell is most nearly approaching to Succinea cam- 

 pestris. 



On a new genus of Pholadid^, with notices of several 



NEW species and OF A REMARKABLE SPECIMEN OF PhOLAS 



CALVA IN Mr. Cuming's Collection. By G. B. Sowerby, 

 JuN., F.L.S. 



Among the species of Pholades there are various modifications of 

 structure, particularly with regard to the form, position and number of 

 the accessory valves, and the test enclosing the anterior hiatus of the 

 shell in some species, which are very interesting and important, and 

 have given rise to various proposals for the division of the species into 

 distinct genera. The propriety or otherwise of such divisions it is 

 scarcely worth while to argue about, as it is after all a mere question 

 of convenience, whether such modifications should be expressed by 

 arranging the species in so many genera of a family, or so many sub- 

 divisions of a genus. It will be sufficient for my present purpose to 

 remark, that there is one character in which the Pholades, whether 

 open or closed, with or without accessory valves, cup-bearing or tube- 

 forming, all agree, and that is, in the curved processes commencing 

 under the hinges inside the shell. In the genus now to be described 

 these are wanting, and this fact removes the hesitation which might 

 have been felt in attempting to establish a generic distinction from the 

 other characters, however well-marked and interesting. 



20* 



