MARSHALL : ADDITIONS TO " BRITISH CONCLIOLOOY. 12"] 



Cantraine's specific name suhpicta has precedence of matiiiorata by 

 three years, and that given by Say {latefa/is), if applicable to the 

 present species, is still older ; but viarmoraia is now in general use.^ 



M. COStulata Risso. — -Alderney (Marquand) ! Swansea (Jeffreys); 

 Freshwater West (Vaughan and J.T.M.). I once found a valve 

 among some northern shells gathered on the beach at Durness in 

 Sutherlandshire, and although this valve was beach-worn like the rest, 

 there is a possibility of error. Al. coshdata is almost exclusively 

 southern, the only exceptions being the Welsh ones recorded above. 



M. discors var. semilsevis Jeff.=var. IcBvigata Gray=var. sub- 

 striata Gray=var. Icevis Beck. — Benbecula Sound lof. 



All the preceding names are scarcely required for the same form ; 

 they only differ in colour or degree of sculpture, which is extremely 

 variable even among specimens living together. At one extreme, 

 Jeffreys' variety is small and yellowish-green, while at the other Gray's is 

 large and purplish-black, caused merely by a difference of environment. 

 I have all these four forms, besides the type, from Arctic localities. 



M. nigra Gray. — This species, as well as several other yJ/(7^/^/c?r/(7, 

 British and foreign, has been given the name of discrepatis. They 

 attain a large size on the Doggerbank and off Aberdeen, reaching up 

 to 2^in. in width. 



Crenella pellucida Jeff. — Adventure Bank 92f. ('Porcupine') ! 

 Sooloom Bay, Tripoli i2of. (Shearwater)! Even this mite of a 

 bivalve is occasionally pierced by a gastropod, which leaves little more 

 than the margins of the shell. 



Nucula sulcata Bronn. — Pladda, Clyde, 33r, abundant and fine 

 (Knight) ! 



N. nitida var. radiata Marsh. — This is figured by Jeffreys as a 

 "streaked variety. ''- 



N. tumidula Malm has been dredged off the Butt of Lewis in 

 545f. by the Scottish Fishery Board (Simpson) ! and in the same 

 district in 53of. by the ' Knight Errant.' 



N. corbuloides Seg. was also dredged with the preceding species 

 by the ' Knight Errant,' and in the Atlantic off Ireland by the 

 ' Porcupine.' Sowerby gives a figure under this name,* but it has no 

 resemblance to the actual shell. 



A valve of Malletia obiiisa M. Sars, a rare species, has been dredged 

 by the Scottish Fishery Board in igyf., midway between the Shetlands 

 and Norway (Simpson) ! 



Leda pusilla Jeff.^— S. W. Ireland 3o-4of. (R. I. A. cruise) ; 

 Antrim ((Chaster). 



1 Jefifreys : Moll. 'Lightning' and ' Porcupine,' P.Z.S., 1879, p. 568. 



2 Brit. Conch,, vol. v., pi. xxix., fig. 3a. 



3 Illiis. Ind. Brit. Shells, pi. xxvi., fig. 17. 



4 Jeffreys, Proc. Zool. Soc, 187Q, p. 580, pi. xlvi., fig. 6; Chaster, Irish Naturalist, Illay, 

 1897, vol. vi. 



