362 MARSHALL: ADDITIONS TO “BRITISH CONCHOLOGY.” 
able paper on the genus’ simultaneously with one from 
Dr. Jeffreys on the same subject; and while the former 
insists on the crenulated margin being “a mark of 
maturity” and “of importance in the discrimination of 
species,” the latter cites instances to show the contrary. 
It is notorious that A. friangularvis has a smooth and a 
crenulated form, which were originally described as two 
species by Montagu, and that 4. su/cata and its var. scotica 
are in the same category ; but no one would now separate 
them. And Mr. Smith cites 4. e//iptica as a good species 
on account of ‘“‘the constant absence of crenulations within 
the margin of the valves in adult specimens.” Undoubtedly 
if the crenulated margin is a specific character, the var. 
elliptica should rank as a species, though it is connected 
with the type by intermediate forms which may be assigned 
to either. Another point which militates against the 
crenulated margins being considered specific, is the fact 
that some of the Veneride are crenulated, while others 
are plain. 
A. sulcata Da C.—Herm and Scilly Islands—one dredged off 
the former island by myself, and two others, with some 
young valves, from Scilly, by Smart and others. 
I noticed a perfectly white specimen in Admiral Bed- 
ford’s collection, dredged off the West of Scotland. The 
fry are white, smooth, and polished. 
Jeffreys’ figure is a good one; Sowerby’s too triangular, 
with an insufficient number of ribs. Of the var. ed/iptica, 
Jeffreys’ figure is correct in outline, but the ribs too promi- 
nent, while in Sowerby’s they are too obsolete, and the 
beaks too acute. 
Var. paucicostata Jeff—Shape as variable as the type; 
ribs 20—24. 
1. J. of Conch., vol. 3, pp. 196-232, 1881. 
2. Moll. ‘Lightning’ and ‘ Porcupine,’ Proc. Zool. Soc., 1881, p. 711; and J. of 
Conch., vol. 3, pp. 233-4- 
J.C., viit., Apr. 897 
