BIVALVIA. 93 
I have seen but one specimen of this species from the Red Crag, which was found 
by myself nearly twenty years since, and I presume it, therefore, to be rare in that 
Deposit ; one specimen also from the Cabinet of Mr. Leckenby, found at Bridlington, 
appears to belong to the same species, and they are both assigned to the recent 
British one, and to the more ventricose or less transverse variety: specimens of the 
recent shell, corresponding in every respect with our Crag fossil, have been obtained 
by myself on the shore at low water on the Coast of Suffolk, and I have no hesitation 
in pronouncing upon their identity. 
5. LEDA PERNULA, Miller. Tab. X. fig. 13, a—e. 
ARCA PERNULA. Miill. Besch. Berl. Naturf. Fr., iv, 57, 1779, fide Loven. 
— Marri. Chem. Conch. Cab., t. vii, t. 206, fig. 550, 1784. 
— rostrata. Gwmel., fide Lovén. 
— — W. Wood. Ind. Test., p. 47, pl. 10, fig. 43, 1825. 
— FLuyiaTitis. Schrét. Flusc., p. 187, pl. 9, fig. 2, fide Desh. 
Nucvta FLuviaTILis. G. Sowerby, Genera No. 17, fig. 3. 
—  opLtonca. Brown. Lllust. Conch. Gr. Brit., pl. 25, fig. 17, 1827. 
— rostrata. G. Sowerby..Conch. Ilust., fig. 12. 
— — Desh. 2d ed. Lam., t. vi, p. 504, 1835. 
—  Jacxsonr? Gould. Inv. Massach., p. 102, fig. 65, 1841. 
— _ Dekay. Nat. Hist. New York Zool., p. 181, pl. 12, fig. 213, 1843. 
—  TENUISULCATA. Couth. Bost. Journ. Nat. Hist., vol. i, p. 64, pl. 3, fig. 8, 1839. 
Lepa rostrata. Forbes. Mem. Geol. Surv., p. 420, 1846. 
—_ — Schum. Essai, &c., p. 173, pl. 19, fig. 4, a—4, 1817. 
— peERNULA. Lovén. Ind. Moll. Scand., p. 34, 1846. 
Spec. Char. Testa transversd elongata, anticé rotundatd, postice duplo longiori, in 
rostrum obtusum attenuata, concentricé striata. 
Shell transverse, elongate, anterior side rounded, posterior twice the length and 
attenuated, terminating in an obtuse beak, concentrically striated. 
Longest diameter, Zths of an inch. 
Locality. Mam. Crag, Bridlington. 
Clyde Beds. 
One specimen (fig. 13, ¢) belonging to Mr. Bean, found at Bridlington, and 
obligingly lent to me by that gentleman for the purpose of description, appears to 
be somewhat different from the preceding, it corresponds with the recent form found 
in the Boreal Seas of Europe, and which is most probably also a native of the 
Northern Coast of America. Our fossil is not in good condition, being compressed 
and slightly broken, and its natural form in consequence somewhat distorted, but it is 
sufficiently perfect to permit of a presumed evidence of identity with the recent species. 
It is more inequilateral than the preceding species, larger, and with finer concentric 
striz, corresponding with the figure and description of JV. ¢enuisulcata, Couthouy, and 
of which, probably, JV. Jacksoni, Gould, is only a variety. Fig. 13, a, 4, is the repre- 
sentation of a specimen from the Clyde Beds, given to me by Jas. Smith, Esq., of 
