CORBULA. 187 



sloping ; that of the anterior side is ahnost straight ; that 

 of the posterior is very slightly retuse. There is no particu- 

 lar depression on either side of the umbones, which latter 

 are tolerably prominent, and not peculiarly unequal in size 

 or projection. The umbonal ridge is obsolete in both 

 valves ; the interior surface, which, in the few specimens 

 examined by us, partakes of the external colouring, is said 

 to be typically pink. The small example, from which the 

 enlarged figure has been engraved in our plates, is only a 

 little more than a quarter of an inch in length, and about 

 one-third less in breadth ; the width, however, of the 

 fully adult shell is five-sixteenths, and the entire length 

 full seven-sixteenths of an inch. 



The supposed Weymouth specimens, collected, as Mr. 

 Jeffreys assures us, by Mrs. Rd. Smith, of Bishopstoke, 

 near Bristol, were found enveloped in a kind of net-work 

 of broken cases of terehellfe^ and other loose textures of 

 known British origin ; a strong, though not conclusive 

 argument, for their being esteemed indigenous. It is 

 taken chiefly in Sweden and the north of Europe. 



0. ovATA, Forbes. 



Plate IX. Fig. 15. 



Corlda ovala, Forbes, Malacol. Monensis, p. 53, pi. 2, f. 8, 9.— Brown, lllust. 

 Conch. G. B. p. 105, pi. 42, f. 32, 33.— Reeve, Conch. Iconica, 

 Corbula, pi. 3, f. 18. 



Although the original describer (E. F.) of this shell 

 took it himself from the root of a Laminaria cast ashore at 

 Ballaugh, in the Isle of Man, he prefers leaving it among 

 the doubtful species rather than stamp with the authority 

 of mature deliberation the previous introduction into our 

 Fauna of a species which by its presence there would vio- 



