ARCA. 241 



brokeshire (Jeffreys), Exmouth (Clark and Jeffreys), 

 Tenby and Milford Haven (Lyons), Lundy Island in 

 seven to twenty-seven fathoms (M' Andrew), off the 

 Norfolk coast (Captain Owen Stanley), Filey in Yorkshire 

 (Strickland), Berwick Bay (Dr. Johnston), Ireland (Mr. 

 Dillwyn), Bantry Bay (Mrs. Puxley). 



It is common in seas to the south of Britain, and abun- 

 dant in the Mediterranean. 



A. RARIDENTATA, ScarlcS Wood. 



Very small, white ; posterior end greatly the broader : hinge 

 with only three or four teeth on either side of the beak. 



Plate XLV. fig. 8. 



Area raridentata, Searles Wood, Cliarlesworth's Magaz. Nat. Hist. vol. iv. 



(1840), p. 232. pi. 13, f. 4 (fossil). — Thompson, Annals 



Nat. Hist. vol. xviii. p. 385. 



Area Feetunouloides, " Scacchi, Notizie, etc. p. 25, no. 62, pi. 1, f. 12," 



(Philippi). — Jeffreys, Ann. Nat. Hist. vol. xix. p. 



313. — Philippi, Moll. Sicil. vol. ii. p. 44, pi. 15, f. 8. 



— LoVEN, Index Moll. Scandinav. (from specimens.) 



The general aspect of this elegant little Area is rather 

 peculiar, inasmuch as the radiating ribs, so universal in 

 the recent species of this genus, are either almost absent 

 or barely indicated ; and the shape, which is nearly semi- 

 circular, but of great disparity in breadth at the two ex- 

 tremities, is far from an ordinary one. The valves, which 

 are tolerably strong, almost opaque, and very nearly equal 

 to each other in size and depth, are swollen at the umbones, 

 from whence they diminish in convexity in nearly equal 

 ratio on either side. They are of an uniform whitish hue, 

 both within and without, and are decussated by fine close- 

 set lamellar concentric strise, and still more delicate radiat- 

 ing striulse, the former being chiefly evident at the umbones, 



VOL. II. II 



