Zoological Society. 369 



The glossy epidermis, which is apparently destitute of any distinct 

 beard, although sufficiently rough on the anterior slope to render its 

 occasional presence not improbable, ceases entirely just before reach- 

 ing the hinge-margin, leaving a long narrow strip of dull dusky 

 purple. Its general shape closely resembles aJbicosta of Lamarck, 

 with which briefly-described species it has doubtless been confused 

 by the majoritj' of collectors. That species, however (whose original 

 type I carefully examined at Paris), differs both in other respects and 

 by the clear fawn-colour of its epidermis. 



MoDioLA STRiGATA. Mod. tcstd parvit, tenuissimd, siibdejjressd, 

 oblongd, virescente, strigis undulatis fiisco-purpitreis, irrcgiilariter 

 jnctd ; latere aniico radiatim striafo, dilafaio, n/iguli dorsalis cx- 

 perte ; latere postico brevissimo, longitudinaliter costidato ; mar- 

 gine cardinali clongato, conve.ro ; aniico arcuuto ; ventrali medio 

 convexiusculo. Long. 0'25 ; lat. 0"50 poll. 

 Hab. Sibango, isle of Zebu ; in ten fathoms, sandy mud. Mus. Cu- 

 ming, Hanle}'. 



For this and the succeeding species w-e are indebted to the re- 

 searches of H. Cuming, Esq., in the Philippine Islands. The shell, 

 though small, is far from inelegant, and unites the contour of the 

 British discrepans with the zigzag markings of the African Owenii. 



MoDioLA ARCUATULA. Mod. tcstd elongutd, angustd, subarcuatd, 

 compressd, Icevigatd, tenuissimd, anguli dorsalis experte ; sub epi- 

 dennide fulvo-viridescente, strigis undulatis, purpureo-brimneis, 

 antice transversim ornatd ; casta umbonali pallidd, prominente ; 

 margine cardinali elongate, antico brevi, valde arcuato ; ventrali 

 incurvato ; extremitate anticd dilatatd, rotundatd ; posticd rotun- 

 datd, prominente, valde attenuatd, costellis paucis radiatd ; super- 

 fide internd, antice purpurea tinctd. Long. O'oO ; lat. I'oO. 

 Hab. Singapore, at low water, AIus. Cuming, Hanley. 

 Belonging to that division of Modialce which is destitute of any 

 dorsal angle, it is remarkable for its narrow sickle-shaped contour, 

 and the few narrow ribs of its posterior extremity. 



MoDiOLA SORDIDA. Mod. tcstd oblongd, ventricosd, epidermide 

 olivaced indutd ; area anticd lamellis concentricis , membranaceis, 

 cinereo-fulvis, vestitd ; lamellarum margine barbato ; casta umbo- 

 nali prominente ; angula dorsali abtusissimo ; margine cardinali 

 breviusculo, pariim elevato ; antico elongato, in adultis 7-etusa ; ven- 

 trali incurvato ; extremitate posticd brevissitnd,obtusissinid ,- super - 

 ficie internd, antice purpurea tinctd. Long. 1-25 ; lat. 2-65. 



Hab. ? Mus. Metcalfe. 



The shape of this ugly species closely resembles that of M. Mo- 

 diolus, but the colour of its epidermis and its peculiar beard will easily 

 distinguish it. This latter appendage is composed of a duU-lookino-, 

 membranaceous, ashy-coloured substance, formed of lamellae, which 

 near the ventral edge curl upwards towards the ])eaks ; the edo-es 

 are here and there fringed with elongated lanceolate filaments. The 

 umbonal ridge is edged posteriorly by a paler streak, which is not 

 sufficiently distinct however to be termed a ray. 



