232 ARCADE. 



of Sicily, and other places abroad, and in the Clyde Pleis- 

 tocene beds, where it was observed by Mr. Smith of Jor- 

 dan-Hill. 



SPURIOUS. 

 L. Montagui, Gray. 



Area rostrata, Mont, (not Chemn. Dillw. nor Brug.) Test. Brit. Suppl. p. 55, 



pi. 27, f. 7.— Turt. Conch. Diction, p. 11. 

 Nucula „ Turt. (not Lam.) Dithyra Brit. p. 178. — Flem. Brit. Anim. p. 

 402. — Brit. Marine Conch, p. 106. — Brown, Illust. Conch. 

 G. B. p. 84, pi. 33, f. 16.— Hanl. Recent Shells, vol. i. p. 168, 

 suppl. pi. 20, f. 1. 

 „ Montagui, Gray, Ann. Philosoph. 1825, p. 138. 

 „ curvirostra, Sowerby, Concholog. Illustr. Nucula, f. 5. — Reeve, Conch. 



Systematica, pi. 85, f. 5. 

 „ rccurva, Conrad, Journ. Acad. Nat. Sci. Philadelphia, vol. vi. pt. 2, 

 p. 262, pi. 11, f. 21.— Hanl. Recent Shells, vol. i. p. 170. 



A native of Liberia, &c; introduced by Montagu, as dredged 

 in Scotland off St. Abb's Head, by Mr. Laskey. Probably from 

 ballast. 



In consequence of the Pleistocene Tertiary beds of clay 

 on the west coast of Scotland being often laid bare below 

 low-water mark, fossil shells are frequently brought up in 

 the dredge along with recent ones, and as often cast on the 

 shore. Owing to their extremely fresh aspect, even the 

 epidermis in many instances being preserved with its pris- 

 tine colours and lustre, it is very difficult to say at a glance 

 whether such specimens be not the exuvia of animals yet 

 living in the neighbourhood. This difficulty is yet further 

 increased by the possibility which always exists of the 

 species in question yet lingering alive (as indeed we have 

 seen in the case of Leda pygmaa), in some limited tract or 

 Boreal patch in our seas. Until, however, such is proved 



