386 MARSHALL: ADDITIONS TO “ BRITISH CONCHOLOGY.” 
M. stultorum L.—This species is very liable to become in- 
commoded by sand-grains, which enter the shells and are 
then cemented over by the animal. Among specimens 
dredged on the Doggerbank, which is comparatively shallow 
and subject to heavy ground swells after gales, fully 30 per 
cent. were in this condition. The fry are triangular, like 
the adult, and wot oval. 
The figures both of Jeffreys and Sowerby are incorrect. 
If an actual specimen be placed on these figures, it will be 
seen that they are too triangular, and in Sowerby’s figure 
the beaks are sharp instead of being obtuse. 
Var. cinerea Mont.—Shell of the same texture as the type. 
M. glauca Born.—Jersey, in coarse gravelly sand at low spring 
tides, and Herm, confined to a small bank of very fine sand 
which is rarely uncovered by the tides. The Jersey specti- 
mens have a dull, dark, and coarse epidermis, owing to the 
nature of the habitat, but those from Herm are much 
lighter in colour, and have a beautiful glistening epidermis. 
The Jersey shells are mostly of a plain cream colour 
beneath the epidermis, and correspond to the Cornish 
valves of var. /ufeo/a. 
I am not sure that JZ. glauca has been found at 
Guernsey, though Jeffreys quotes it on the authority of 
Dr. Lukis. It is very rare at Herm, but common in the 
Jersey habitat, where several dozen may be found on a 
favourable tide by the initiated. The epidermis blisters 
badly on immersion in hot water, and the best way to 
extract the animal is to wait until it opens its valves, and 
then cut the muscles suddenly with a sharp and thin knife. 
I have kept specimens ina pan of sea-sand, occasionally 
moistened with sea-water, for six weeks, and they have then 
been fresh and active. 
Lutraria elliptica var. intermedia Sow.—I do not know 
that this variety has been described, but I find the name 
J.C., viii., July 1897. 
