PHOLAS. 109 



species differs from P. dactylus in its more convex 

 shape and thinner texture ; the front gape being much 

 narrower; not having any dorsal cells, nor more than 

 a single shield ; and in possessing a strong and remark- 

 able fold on the hinge-plate. 



The specific name was given by Lister. Spengler 

 described and figured the present species as the P. 

 papyraceus of Solander ; but his description, quoted by 

 Spengler, is more like that of a young P. crispata. It 

 is also the P } dactyloides of Delle Chiaje, and Barnea 

 spinosa of Risso. The P. cylindrica of J. Sowerby, 

 from the Red and Coralline Crag, appears to be inter- 

 mediate between the present species and the next. 



K*J jU7 3. P. PARVA*, (Pennant.) 



P. parvus, Penn. Brit. Zool. iv. p. 77, pi. xl. f. 13? P. parva, F. & H. 

 i. p. Ill, pi. iv. f. 1, 2, pi. ii. f. 2, and (animal) pi. F. f. 3 & 3 A. 



BODY oval, milk-white : mantle invested at its edges by a 

 thin membrane : tubes marked inside lengthwise with alternate 

 brown and white stripes ; orifices scalloped, but neither are 

 cirrous; sheath thick, reddish-brown, covered with nume- 

 rous granular papillae ; these become larger towards the ex- 

 tremity of the sheath, which is encircled by a fine pile or 

 fringe : foot oval when at rest, rounded in front and pointed 

 behind when protruded, and attached by a long cylindrical 

 fleshy stalk. 



SHELL oblong, somewhat compressed, rather solid : sculpture, 

 very numerous transverse rows of imbricated and flexuous 

 ridges, which are puckered or flounce-like on the crests formed 

 by the intersection of slight and less numerous longitudinal 

 ribs ; these markings are more crowded on the anterior side, 

 and in the adult gradually disappear towards the posterior 

 side, which is smooth or only exhibits some irregular lines 

 of growth ; there are seldom prominent and sharp prickles as 

 in the preceding two species : colour white, sometimes slightly 

 stained with brick-red from the matrix in which the shell is 

 imbedded : epidermis light-yellowish and irregularly fibrous, 



* Small. 



