250 lucinid^:. 



Molluscorum litora Scandinavise occidentalia habitan- 

 tium/ is not uncommon on the coasts of Norway and 

 Sweden; but it has not been found in our seas. I 

 venture to regard it as a large variety of A. flexuosus. 

 Some remarks will be found on the subject when I come 

 to treat of the next species. 



2. A. Croulinensis *, Jeffreys. 



Clansina Croulinensis, Jeffr. in Ann. Nat. Hist. vol. xx. p. 19 ; ser. 3. ii. 

 p. 122, pi. v. f. 2, a-c (young). 



Shell obliquely oval, tumid, of a moderate thickness, 

 opaque except in the young state, rather glossy : sculpture, 

 numerous and fine but irregular concentric striae : colour white : 

 epidermis slight : margins rounded on the anterior side, as 

 well as in front, and slightly angular on the posterior side, 

 which is indented by a double but short furrow : beaks small 

 and prominent, much more recurved than in the last species, 

 almost contiguous and central: lunule indistinct: corselet 

 narrow but well denned by the upper furrow : ligament slight, 

 not visible outside ; ligamental groove sloping inwards : hinge- 

 line obtusely curved, occupying not one-fifth of the circum- 

 ference: hinge-plate rather narrow but thick, almost all of 

 it lying on the posterior side ; the tooth-like folds are as in 



A. flexuosus, but very much stronger and more conspicuous: 

 inside highly glossy, iridescent, and smooth ; margin thin and 

 plain : pallial scar indistinct : muscular scars oval. L. 0*15. 



B. 0-135. 



Habitat : Skye and Shetland, in muddy sand, from 

 45 to 85 fathoms ; rare. 



This shell, compared with specimens of A. fleocuosus 

 of a similar size and age, is longer and more oblique, as 

 well as proportionally more solid; the margin of the 

 anterior side is curved, instead of being nearly straight 

 and truncate; the furrows on the posterior side are 

 scarcely visible when viewed in front ; the beaks are 



* From its having been first found near Croulin Island, in the He- 

 brides. 



