GA8TER0P0D0US MOLLUSCA OF BERWICKSHIRE. 37 



2. F. pellucida^ shell corneous, pellucid, smooth, rayed with inter- 

 rupted azure blue lines from the vertex to the broad end ; apex 

 black, lateral, leaning ; base ovate, the margin thin and smooth. 

 Length i^ths; breadth /gths. Flem. Brit. Anim. 287. 



Hab. On Laminaria digitata, common. 



When young, the vortex touches the marginal line, but in full grown siwci- 

 mons it is considerably raised. 



3. P. lavis^ shell depressed, conical, thickish, corneous, subpellucid, 

 rayed with brown and interrupted blue lines diverging from the 

 apex, smooth ; apex lateral, inclined, resembling a small shell 

 placed on a larger one ; margin smooth ; interior iridescent. 

 Length /ot^s ; breadth ^^gths. Flcm. Brit. Anim. 287. P. 

 cfiorulea, Mont. Test. Br. Sup. 162. 



Hab, About the roots of Laminaria digitata, common. 



Animal white, with continuous branchice. Dr Fleming considers this dis- 

 tinct from the preceding, and it is not very easy to find intermediate 

 specimens, to prove that they are not so ; yet I cannot but agree with 

 those naturalists who consider the differences between them to depend 

 entirely on differences in their locality. " The Patella pellucida of 

 Montagu is synonymous with the P. ccerulca of the same author, the 

 former having been founded on specimens taken from the stalk, and 

 the latter on individuals obtained from the flattened frond of the Fu- 

 cus, on which the species usually takes up its abode : it is indeed by no 

 means rare to find specimens in which the animal has moved from one 

 of these positions to the other ; and, in such cases, the apex of the shell 

 represents P. cccrulea and the base P. pellucida, or vice vertd.*' — J, E. 

 Oraij, in Phil. Trans, for 1833, p. 782. The very reverse of what is 

 here stated, relative to the habits of these supposed species, is the 

 fact, as Mr Gray subsequently ascertained ; but his conclusion appears, 

 nevertheless, to be correct. P. Irovis lives ensconced snugly in holes, 

 which it has eaten out of the under side of the root of the tangle ; 

 and it is interesting to see them instinctively select a site, so secure 

 from foe and storm, and at the same time where food is ever at hand. 

 The holes are often an inch or rather more in depth, and the convex 

 form of the face of the shell may arise from the animal living in an 

 almost hemispherical cavity. Aiin. Nat. Hist. vol. i. p. 483. 



Chiton. Linrueus, 



*• Shell oval, consisting of eight arched pieces arranged across the 

 body of the animal in a scries overlapping each other, their ends set in 

 the skin, which forms a rim around them.'' Gould. 



1. C. fasciculaiis, shell oval, dusky or cinereous ; valves raised and 

 striated down the middle, coarsely granular, the granules flattish ; 

 marginal band armed with tufts of short spines, and fringed. 

 Length from 6 to 10 lines. Flcm. Brit. Anim. 288. Zoitr, in 

 Zool. Journ. ii. 96. Sowerbtf''8 Gen. fig. 3. Brown's Illust. pi. 

 35, figs. 5, 8. 



