78 



DK Johnston's catalogue of bivalved shells. 



Pectenid^. 

 Pecten maximus. 

 opercnlaris. 

 lincatns. 

 Tarius. 



Pecten obsolctus. 



spinosus, Brown, Illus. pi. 33, 

 fig. 8. 

 Lima fragilis. 



II. DIIklYAIEIA. 



Arcade. 



Area f asca. 

 Nucula nuclea. 

 minnta. 



Mytilid^. 

 Mytilus edulis. 



var. pellncidns. 



var. subsaxatilis, Williamson, in 

 Mag. Nat. Hist. vii. p. 354, 

 fig. 48. 

 Modiola vulgaris.^ 



var. barbatus. 

 discors. 

 discrepans.^ 



IlNIONIDiE. 



Anodon anatinus. 

 cygnens. 



CONCHACEa;. 



Cardium edule. 



echinatum.* 



IsBvigatum. 

 Donax trnnculus. 



Tellina fabtda. 



tenuis. 



crassa. 

 Psammobia florida. 



Ferroensis. 



solidula. 

 Cyprina islandica.* 

 Mactra solida. 



truncata. 



snbtruncata. 



elliptica, Brown, Illus. pi. 15, 

 fig. 6. 



stultornm. 

 Kellia suborbicularis.^ 



rubra. 

 Cyclas corneus.^ 



amnicus. 

 Pisidium pulcbellum, Jenyns. 



pusillnm, Jenyns. 

 Astarte Danmonise. 



Scotica. 



compressa. 

 Cytlierea exoleta.'' 



lincta. 



ovata. 



^ Lamarck has arranged " Modiola" amongst the " Monomyairia," but M. vulgaris 

 has three, or more properly four, adductor muscles: viz., one near each end of the 

 shell, and two lesser ones towards the centre of the body. 



" The foot of this and the preceding is very extensible, and when extended is several 

 times longer than the shell, and almost filiform. By fixing this foot at the furthest 

 point to which it can be stretched, and then dragging the shell forwards, the animal 

 moves with considerable rapidity ; and swims readily in a reversed position on the 

 surface. 



^ Foot of a rich pink colour, long, somewhat compressed, with a bend or elbow, 

 whence it tapers to an olituse point : cloak with a plain thin margin, about a line in 

 breadth, behind which it is suddenly thickened, and at regular intervals raised into 

 glandu.lous warts or tubercles, corresponding to the grooves in the shell : respiratory 

 and excrementitious apertures ercircled with tentacular filaments ; labial appendages 

 long, strongly striate on one side. 



* Animal white ; the cloak open, with a thickened minutely crenulate border, the 

 orifices of the passages encircled with papillas ; foot broad, compressed, the margin 

 plain, and somewhat undulate. 



^Animal clear white; syphonal tube single, cylindrical, with a plain aperture; 

 foot compressed, tapered, thin, and flexible. 



^ Often found in marl. 



''Animal with a broad compressed foot; syphonal tubes united throughout, with 

 plain apertures. 



