EEPORT ON THE'LAMELLTBRANCHIATA. 143 



Circe gibbia (Lamarck). 



Ci/fherea gihbia, Lamarck, Anim. sans vert., vol. v. p. 577. 



Cytherea gibbia, Sowerby, Gen. of Shells, fig. 3. 



Circe gibbia, Sowerby, Thes. Conch., pL cxxxvii. figs. 4-7. 



Circe gibhia, Reeve, Conch. Icon., fig. 21, a-d. 



Venus (Ci/tJierea (Crista)) gibbia, Romer, Mai. Blatt., 1863, p. 17. 



Venus (Cytherea (Crista)) gibbia, Romer, Monog. Veneridffi, vol. i. p. 176, pi. xIviL fig. 2. 



Habitat. — Station 188, south of New Guinea, in 28 fathoms; green mud. 



This species has been recorded from several localities in the Indian Ocean, from the 

 Philippine Islands, and from New Caledonia. 



Cii'ce bermudensis, n. sp. (PI. II. figs. 1-1 6). 



Testa parva, trigono-rotundata, paulo insequilateralis, albida (?), mediocriter convexa, 

 utrinque rotundata, Uiis radiantibus et concentrieis tenuibus cancellata. Margo dorsi 

 utrinque valde declivis, postice leviter arcuatus, antice rectiusculus, ventralis parum 

 curvatus. Umbones mediocres, aliquanto ante medium siti, acuti, incurvati. Lunula 

 impressa, late lanceolata. Dentes cardinales normales, postico valvse dextr^ et mediano 

 sinistrse maximis. Sinus pallii indistinctus. 



This species is longer than high, and becomes proportionately longer as it increases. 

 It is a little inequilateral, the anterior end, as is usually the case in the Veneridae, being 

 shoi'ter than the posterior. It is beautifully ornamented with fine concentric lirse, which 

 are crossed by others equally slender radiating from the apices, the points of intersection 

 being somewhat granular. It is probably whitish, but I am unable to speak with 

 certainty upon this jaoint, as all the valves before me are more or less worn. It is rather 

 rounded when very young, but becomes more trigonal in older shells, the umbones being 

 more elevated, and thus producing this appearance. The dorsal margin descends con- 

 siderably on both sides, is rather longer and a trifle arcuate behind, in front being 

 nearly rectilinear. The two ends are subequal, the posterior, if anything, rather 

 narrower than the anterior, the reverse being the case in the earlier stages of growth. 

 The ventral margin ascends more in front than behind, and is not very much curved at 

 the middle. The lunule is broadly lanceolate, faintly sunken, defined, and exhibits lines 

 of growth. The hinge is normal in construction, the hinder tooth in the right valve 

 and the central one in the left beine' rather laro;er than the others. The muscular 

 impressions and the pallial line are too distinct for description. 



Length 7 mm., height 6|, diameter 4^. 



Habitat. — Station 33, off Bermuda, at a depth of 435 fathoms ; coral mud. 



