ON THE ACEPIIALA. 375 



Cynthia coriacea, Alder and Hancock. 



"Body elongated and cylindrical when extended, nearly 

 liemispherical -when contracted, of a pale brownish colour, at- 

 tached to shells, etc. by a broad base, equalling the diameter of 

 the body. Apertures terminal, approximating, tubular, nearly 

 equal in size, pale, with a faint line of red round the margins. 

 Outer tunic rough, coriaceous, transversely wrinkled and longi- 

 tudinally furrowed, covered with minute granules. Inner tunic 

 thin, white, sometimes spotted with brown. Ovaries large and 

 white, lining the tunic with cylindrical convolutions. Branchial 

 sac thin, with about ten longitudinal folds, and finely reticulated ; 

 the longitudinal fibres strongest. Length nearly an inch ; breadth 

 half an inch. From the fishing-boats at CuUercoats with the 

 last, but less common. 



" This species differs from the preceding in having both the 

 apertures terminal, and placed near together, as well as in the 

 minute granulations of the surface. It is capable of greater 

 contraction and elongation than most of the other species, and in 

 the two states, might be taken for different animals. It has 

 sometimes small corallines attached, but we have not observed 

 any Modiolce imbedded in its skin." — Ald. Cat. p. 102. 



In our account of Salpa, Dr. Fleming is stated to have 

 observed great numbers on the coast of Caithness in the spring of 

 1821. It should have been "on the north coast of Sutherland- 

 shire and the Hebrides," in autumn. 



LAMELLIBEANCHIATA. 



In our plates of the animals of bivalves, there are three figures 

 which are seriously in error. One is Cyprina Islandica, which, 

 by an oversight of the engraver, is represented with the beak of 

 the shell towards the siphonal extremity, instead of from it(see 

 plate M. fig. 4.) — The second is Turtonia purpurea (plate 0. f. 1), 

 which should have the siphon projecting from the long end of 

 the shell instead of the short one : of this animal a fresh figure 

 will be given. — The third is Xylophaga dorsalis, respecting which 

 curious mollusk we have received new and very important infer- 



