MARSHALL: ADDITIONS TO 'BRITISH CONCHOLOGY.' 247 



C. papillosum var. obliquata Monterosato. Shell more 



globular and oblique. Mediterranean. I have this variety 



from Guernsey, i8 fathoms. 

 Venus gal Una var. alba. Mr. Somerville has inserted this 



in his list for the pure white form. 

 Psammobia tellinella var. lactea Marsh. Shell milk 



white. Found with the type, but scarce. 

 P. tellinella var. purpurea Marsh. Uniform purple. 



Found also with the type, but more plentifully than the 



white variety. 

 Donax vittatus var. cuneata Marsh. Shell having the 



posterior end wedge-shaped (as in Psainjuobia ferroensis) 



instead of obtusely pointed, and more or less gaping. 



Found occasionally in Torbay. 



D. vittatus var. albida Marsh. Milk white under a straw- 



coloured epidermis. Occasionally found with the type. 

 The young are often white, acquiring their colours as they 

 become adult ; but some never become coloured. 



Mactra solida vai-. intermedia Jeff This is intermediate 

 between the type and the var. elliptica (Jeff, in ' Proc. Zool. 

 Soc, 1 88 1, p. 923). It is not uncommon at Scilly, Ten- 

 by, and other places. 



Scrobicularia alba var. oblonga Marsh. Shell of the 

 shape and size of 6'. ?iitida, but having all the other 

 characteristics of S. alba. Guernsey and Torbay, rare. 



S. longicallus Scac The supposed large S. alba found by 

 Jeffreys in the Shetland seas, and mentioned in ' B. C.,' 

 vol. ii., p. 441, as 'about an inch in breadth and of pro- 

 portionate length,' belongs to this species. It differs from 

 S. alba in being ' larger, thinner, and more compressed, 

 not so oval, somewhat flexuous at the posterior end ; 

 cartilage and pit longer and narrower, lateral teeth much 

 longer' ('Lightning' Report, p. 926). It was also dredged 

 in the Little Minch during the ' Porcupine ' cruise. It is 

 figured in Sowerby's Index, but not satisfactorily ; it should 



