1881.] 'lightning' AND * PORCUPINE * EXPEDITIONS. 695 



(, 4. Lepton lacerum', Jeffreys. 



L. lacerum, Jeffr., Les Fouds de la Men, 1872, p. 84, pi. ii. f. 1 1, 

 Ua. 



Shell roundish-oval, nearly flat, solid for its size, semitransparent, 

 and glossy : sculpture, numerous close-set and very fine concentric 

 striae, which are stronger towards the front : colour clear white : epi- 

 dermis mco\\s\nc\xon% : margins rounded at the sides and in front, but 

 at the back exhibiting on each side of the beak, and at equal distances, 

 a small spike-like projection, giving that part a jagged appearance : 

 beah small, central, and semioval : hinye-line tricuspid, occupying 

 about one sixth of the circumference of the shell : cartilage-pit nar- 

 row and perpendicular: hinge-plate broad and strong : teeth (in the 

 only specimen here described), one small and obliquely placed car- 

 dinal, and a rather long ridge-like lateral, which is also placed 

 obliquely on each side of the beak : inside glossy : scars slight. 

 L. 0-1, B. 0-1125. 



' Porcupine ' Exp. 1870 : Atl. St. 1. A single valve only. 



Distribution. Bay of Biscay and Mediterranean ; 35-70 fms. 



This is a small shell ; but I am at a loss to imagine why, on that 

 account, the Editors of the excellent ' Journal de Couchyliologie ' 

 should have made the remark that as to such shells, " les caracteres 

 n'indiquent pas toujours avec certitude I'age adulte." 



/- Scintilla rotunda^ Jeffreys. (Plate LXI. fig. 1.) 



Shell roundish, with an obliquely triangular outline, nearly flat, 

 solid, opaque but glossy ; sculpture, a few slight concentric lines of 

 growth, which are more distinct towards the front, besides some 

 minute irregular pit-marks as in other species of this genus : colour 

 milk-white : epidermis none : margins gently rounded in front and 

 at the sides, somewhat sloping from the beak on the left hand : beak 

 minute, semiglobular or calyciform : hinge-line very short, obtusely 

 triangular : cartilage-pit narrow and placed obliquely : hinge-plate 

 also narrow : teeth (in the single valve here described) consisting of 

 a minute cardinal, and of a ridge-like lateral on each side of the 

 beak ; the lateral tooth on the left side is much larger than the 

 other, which commences with an angular point: iwsi'd^e polished, but 

 slightly pitted: scars indistinct. L. 0*1, B. 0*1. 



' Porcupine' Exp. 1870 : St. 27. 



Distribution. Palermo ; 48-70 fms. (JSIonterosato, as Vasconia 

 rotunda !). 



The hinge of this species does not quite agree with the description 

 of the genus Scintilla given by Messrs. Adams ; but the remarkable 

 texture of the shell is similar, viz. (to use their own words) " the 

 external appearance of some of the species, which consists of a 

 multitude ot very fine punctations, of an opaque white colour, upon the 

 shell, and which deprives them, in such portions, of their transpa- 

 rency." This peculiarity appears to be owing to the want of homo- 

 geneity in the composition of the shell. 



^ Torn. * Bound. 



