REPORT ON THE LAMELLIBRANCHIATA. 169 



The ligament is subexteriial in part and partly internal. The former portion is linear 

 and extends all along the hinder dorsal margin, and is partly concealed by the right valve 

 overlapping the left. The internal portion is not nearly so long, also linear and slightly 

 divergent from the other. The anterior muscular scar is very deep, whilst the posterior 

 and the pallial line are not noticeable. The interior is dull pearly, and obsoletely 

 substriated in a radiating manner. 



Length 10 mm., height 10^, diameter 8. 



Habitat. — Station 122, off Pernambuco, Brazil, at a depth of 350 fathoms ; also 

 Station 24, off Culebra Island, West Indies, in 390 fathoms. 



This species is very remarkable on account of the peculiar character of its sculpture, 

 its ventricose form, and broad rounded upper angles. I have named it in remembrance 

 of the late Searles Wood, author of the genus Verticordia. 



Verticordia quadrata, u. sp. (PI. XXV. figs. 8-8&). 



Testa quadrata, insequilateralis, albida, minute granulata, radiatimque obsolete lii'ata ; 

 margo dorsi utrinque declivis, antice valde concavus, brevis, postice longior, vix excur- 

 vatus, subrectus, rotundato-angulatim in latera ambiens. Marao ventris subangulatim 

 rotundatus, utrinque subrecte adscendens. Lunula cordata, valde excavata. Umbones 

 prominentes, antice bene incurvati. Pagina interna albo-margaritacea, nitida. Cicatrix 

 anterior profunda, postica inconspicua. 



This species is of a peculiar square form, three of the sides being subequal in length 

 and the fourth shorter. It is dirty whitish, everywhere covered with a fine granulation, 

 faintly radiately lirate, decidedly inequilateral, and moderately convex. The anterior 

 dorsal margin is very concave beneath the beaks and rather oblique, the posterior being 

 much longer, nearly rectilinear, and equally sloping. The sides converge towards the 

 base, are straightish (or the posterior is faintly incurved at the middle), run into the 

 ventral outline in a rather sudden rounded curve, and join the dorsal margins in rounded 

 angles. The umbones are moderately prominent, much curved over upon the deeply 

 sunken cordate lunule, and located about one-third of the length from the anterior end. 

 The interior is pearly white, and exhibits a deep anterior muscular scar and two minute 

 pits beneath the lunule (in the left valve), the posterior impression being indistinct. 

 The ligament is partly marginal and partly contained in a narrow groove within the 

 margin. The hinge-line in the left valve is apparently toothless. 



Length 7 mm., height 6|, diameter 5. 



Habitat.- — Station 85, off Palma, Canaries ; depth, 1125 fiithoms ; volcanic mud. 



This species is finely granulose, like Verticordia woodii, but is smaller, more solid, 



(ZOOL. CHALL. EXP. — PART XXXV. 1885.) Mill 22 



