BIVALVIA. 127 
France: Damery, Montmirel, Courtagnon (Desh.). 
Belgium : Les sables de Laecken, de Jette, de Forét, et de Louvain (Wys/). 
This elegant little shell appears to be rare. ‘The ridges on the exterior are elevated, 
distinct, and large, with deep furrows between them; the furrows are nearly as broad as 
the ridges. On the siphonal region there is a distinct and elevated keel, sloping from the 
umbo to the extremity of the siphoni-lateral margin. 
4. Lepa minima, J. Sowerby. Tab. XVII, fies, a—e. 
NucuLa MINIMA. J, Sow. Min. Conch., t. 192, fig. 8, 1818. 
Spec. Char. L. testa minima, ovato-lanceolaté, elongata, tumidd, subequilateral’, 
concentrice striutd striis numerosis prominentibus ; pedi-regione rotundata ; siphoni-regione 
rostrata, sub-acuminatd ; umbonibus minints, approximatis 3 ano magno, lanceolato, angulo 
mediano bipartito, angulo obtusiore conscripto ; cardine crassiusculo, mullidentato ; fossuld 
minima, profunda. 
Shell small, elongately ovate, tumid, nearly equilateral ; pedal region rounded, siphoni- 
lateral pointed; beaks small, approximate, covered with concentric striae or ridges ; 
corselet distinct, elevated in the centre; dental margin thick, with numerous teeth; car- 
tilaginous support small and deep. 
Length, * of an inch; height, sth of an inch. 
Locality. Barton, Bracklesham, Bramshaw, Brook, Higheliff (Zdwards). 
There are three or four species of this genus about the same magnitude, possessing 
many similar characters, which have been found in the British Eocene deposits, and it is 
somewhat difficult to say which was the one intended by Mr. Sowerby for WV. minima. 
The present one is abundant, and probably was the one his figure is designed to 
represent. He says, “'Transversely ovate, convex, transversely striated.” The stric in 
this species cover the entire surface; they are fine and rounded, extending from the 
pedilateral margin to the angular ridge on the slope of the siphonal region, beyond which 
is a large corselet; this is of a lanceolate form, divided by a central ridge, the upper 
portion of which is finely striated. ‘There is a row of angular teeth (at least a dozen) on 
each side of the cartilage-pit. 
There are two varieties of this shell, one of which strongly resembles the figure of 
L. gracilis, Desh. (‘ An. sans Vert. du Bas. de Par.,’ p. 831, pl. 64, figs. 24—26); and 
several differences are presented, as might be supposed, among our numerous 
specimens; some have the pedal region almost smooth, as if from abrasion on that part, 
which is generally buried by the animal in the living state. 
