296 MOLLUSCA FROM THE CRAG. 
proximity to that locality would fairly justify its being so considered, though he refers 
to Lister's figure, No. 276, which is P/. dactylus, not as yet found in the Crag that I am 
aware of. 
Pieces of indurated clay are occasionally met with at Walton Naze that have been 
perforated by this species; and I have a small portion, little more than two inches 
square, and halfan inch thick, full of small specimens. These shells had effected an 
entrance from both sides, meeting in the middle; and one side contains almost as 
many as the other, showing the probability of the stone having been moved by the 
action of the water, to have permitted an ingress at both surfaces. A specimen of 
wood in my possession, from the Red Crag, but now in a lapideous state, contains an 
individual of this species, which, like P/. parva, its very near relative, did not appear 
to confine itself to one kind of habitation. Some of these shells were at times only half 
immersed, as specimens have often the upper portion covered by the remains of a 
membranipora. 
2. PHOLAS CRISPATA, Linnaeus. Tab. XXX, fig. 9, a—e. 
Puouas crispata. Linn. Syst. Nat., p. 1111, No. 25, 1767. 
— _— Penn. Brit. Zool., 1st ed. p. 77, pl. 40, fig. 12, 1776. 
— — Don. Brit. Shells, vol. 1, t. 62, 1801. 
— — Gould, Inv. of Massach., p. 27, 1841. 
— — Dekay. Hist. New York Moll., p. 247, pl. 32, figs. 506, and 506 a. 
_— — Cuvier. Regne Anim., pl. 113, fig. 3, animal. 
— prsFrons. Da Costa. Brit. Conch., p. 243, t. 16, fig. 4, 4. 
— PARVA. Id. Brit. Conch., p. 247. 
— — Donovan. Brit. Shells, vol. 11, pl. 69, 1801. 
— uatus. List. Hist. Conch., lib. i, fig. 379 a, with the animal, 1685. 
SoLEN crispus. Gmel. Syst. Nat., p. 3228. 
ZIRFHA CRISPATA. Gray. List Brit. Moll., p. 53, 1851. 
Spec. Char. Testé ovatd, crassa, subequilateral, anticé breviore, rostrata, et costatd ; 
costis dentato-muricatis, latere postico rotundato ; eatremitatis hiantissimis ; sulco unico 
submediano, obliquo. 
Shell ovate, thick, slightly mequilateral, anterior side the shorter, beaked and 
ribbed; ribs furnished with roughened and prominent denticulations; extremities 
widely gaping: divided by a submedial oblique suture. 
Length, 3 inches. Height, 1} inch. 
Locality. Cor. Crag, Sutton. 
Red Crag, Sutton, Walton Naze. 
Mam. Crag, Bridlington. Fossil, Sweden. 
Recent, Britain, Scandinavia, and N. E. Coast of America. 
Although essentially a boreal species, it lived in the seas of the Coralline Crag, a 
