290 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 Ph. dactj/lus, 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 half an 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 Ph. 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, Linnceus. Tab. XXX, fig. 9, a — c. 



Pholas crispata. Linn. Syst. Nat., p. 1111, No. 25, 1767. 



— — Penn. Brit. Zool., 1st ed. p. 77, pi. 40, fig. 12, 1776. 

 _ _ Bon. Brit. Shells, vol. ii, t. 62, 1801. 



— — Gould. Inv. of Massach., p. 27, 1841. 



— — Dekay. Hist. New York Moll., p. 247, pi. 32, figs. 506, and 506 a. 



— — Cuvier. Regne Anirn., pi. 113, fig. 3, animal. 



— bisfrons. Da Costa. Brit. Conch., p. 243, t. 16, fig. 4, 4. 



— parva. Id. Brit. Conch., p. 247. 



— — Donovan. Brit. Shells, vol. ii, pi. 69, 1801. 



— latus. List. Hist. Conch., lib. iii, fig. 379 a, with the animal, 1685. 

 Solen crispus. Gmel. Syst. Nat., p. 3228. 



ZiRFiEA crispata. Gray. List Brit. Moll., p. 53, 1851. 



Spec. Char. Testa ovatd, crassd, subaquilaterali, antice breviore, rostratd, et costatd ; 

 costis dentato-muricatis, latere postico rotundato ; eoutremitatis hiantissimis ; sulco unico 

 submediano, obliquo. 



Shell ovate, thick, slightly inequilateral, 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, \\ 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 



