BIVALVIA. 125 
1. Lepa amyapatoipes, J. Sowerby. Tab. XVII, fig. 6, a—c. 
Nucuta aMyepaLorpEs. J. Sow. Min. Conch., t. 554, fig. 4, 1821. 
—_— -~ Wetherell, Tr. Geol. Soc., 1834, p. 134. 
— — Morris. Catal. Brit. Foss., p. 217, 1854. 
Spec. Char. L. testa clongato-ovatd, crassd, tumidd, sub-equilaterali ; concen- 
trice striatd, striis oblusis rotundis ; pedi-regione ovato-rotundatd ; siphoni-regione obtuse 
rostrata ; ared dentali crassiusculd ; fossuld connextis minuld, profunda. 
Shell elongately ovate, thick, tumid, glossy, nearly equilateral, and concentrically 
striated ; strize rounded ; pedilateral margin ovately rounded; siphonal region obtusely 
pointed; dental area rather thick ; cartilaginous depression small. 
Length, \ inch ; height } an inch. 
Localities. Wighgate, Potter’s Bar, Wandsworth, Sheppey, Hampstead, Southend, 
Whetstone Park, Finchley, Hornsey (Zdwards and Wetherell), Cuffells (Prestwich). 
This is an elegant shell, and abundant in some localities, but seldom found with the 
valves separated. Casts of this shell (at least what appear to be so) are found at Sheppey. 
‘The nearest approach to this species is WV. Deshayesiana, Nyst (‘ Coq. Foss. Belg.,’ p. 221, 
pl. xv, fig. 8); but that shell differs in. bemg larger, thicker, with a more inflated and 
more prominent umbo ; the stri in the British shell extend to the extreme margins, and 
cover the entire surface, as they do also in V. Deshayesiana. There is a distinctly marked 
corselet as well as lunule on each side of the umbo, with an elevated ridge ; this is not so 
distinctly marked in the Belgian shell, and the siphonal region of this latter species is 
rather the more pointed of the two. There are about fifteen or sixteen denticles on each 
side of the hinge-area of our shell, and the sinus in the mantle-mark is very shallow. 
2. Lepa costunata; Deshayes. Tab. XVIII, fig. 3, a, 0. 
Lepa costunaTa. Desh. An. sans Vert. du Bass. de Par., t. i, p. 829, pl. 65, figs. 8—10, 
1838. 
Spec. Char. L.“ testa ovato-transversd, sublrigond, soliduld, depressiuscula, equilateral, 
anticé obtusd, postice viv rostrata, transversim reguariter suleatdé ; umbonibus minimis, 
conniventibus ; lunuld levigatd, vir distinctd ; ano elongato, lanceolato, conveviusculo, angulo 
obtuso separato ; margine cardinali angusto ; dentibus serialibus m inulissimis, approximatis ; 
fossula ligamenti minutissima.”—Desh. } 
Shell elongate, ovately subtrigonular, strong, somewhat depressed, equilateral ; pedilatera] 
margin ovately rounded; siphonal region scarcely rostrated, covered concentrically with broad 
ridges and furrows ; beaks small; Innuleandistinct ; corselet elongate, shghtly convex, ex- 
