254 AVICULACEiE. 



its outline seems veiy different. Its body (partly, how- 

 ever, from the terminal edge being chipped) seems less 

 narrow, oblique, and produced than usual; the surface 

 is worn smooth, and the preponderance of darker markings 

 causes it to appear rayed with yellowish white on a ground 

 of chocolate brown. 



The animal, which we have seen alive in the Mediter- 

 ranean, is of a yellowish white colour. Its mantle edges 

 are freely of)en; each pendant margin is fringed with a 

 basal range of short closely-set white cirrlii and a mar- 

 ginal row of rather long ones, which, as well as the mantle 

 itself, are whitish, mottled with brown. The branchiae are 

 white. The foot is white, short and small in proportion to 

 the animal, and spins a strong byssus from its basal groove. 



This is a very rare shell, as a British species, and has 

 hitherto been found only towards the South. It was first 

 taken by Miss Hutchins in Bantry Bay, and Mr. Warren 

 has two specimens from the neighbourhood of Dublin. On 

 the English coast it has occurred in Devon and Cornwall. 

 It is more frequent in the Mediterranean Sea.* 



PINNA, LiNN^us. 



Shell very oblique, wedge-shaped, triangular, equivalve, 

 exceedingly inequilateral, more or less thin and fragile, 

 gaping posteriorly ; surface smooth, or scaly, or obliquely 

 furrowed ; beaks terminal. Hinge straight, long, tooth- 



* Turton, in his " Conehological Dictionary of the British Islands," has intro- 

 duced (p. 108) the Avicula Aforio of Leach (Zoological Miscellany, pi. 38, f. 2), 

 but has virtually withdrawn it by omitting the species in his subsequent quarto 

 on British Bivalves. It is very probable that the specimen stated to have been 

 dredged by Mr. Prideaux in Plymouth Sound was only our ordinary British 

 species ; at least nothing in the very brief description militates against the suppo- 

 sition. 



