206 
THE ESSEX NATURALIST. 
fig. 4). The shell is described by Defranee as “ very thin, rounded, 
dilated, upper valve flat, much smaller than the lower ; lamellae 
membranaceous, imbricated and very distinct.” The scales are 
a yellowish brown colour, large and loose, and allow the upper 
valve to sink in when removed. A fine example of this shell is 
in the British Museum collection, and a shell very similar to 
this comes into the lower English Channel, from whence the 
trawlers occasionally bring them in. These grow to a large size, 
one of mine being, length 130 mm., breadth 135 mm. The top 
valve is thin, the horny lamellae projecting nearly half-an-inch 
beyond the margin of the shell. The lower valve is very broad 
and shallow, with numerous costae foliated below, and at times 
purple in colour. 
The McAndrew Coll. (Cambridge) has a cluster of these shells 
from Gibraltar, very delicate in texture, almost transparent. 
It is the Atlantic equivalent of the 0 . edulis of the Eastern British 
coasts, and has probably furnished the name to Mediterranean 
conchologists. 
I obtained, through a fisherman, a number of oysters from 
Caldy Island, collected at low water, in which the upper 
valve is deeply recessed into the lower one. The shells are 
fairly large, roundly subtrigonal, white or porcellaneous 
within, muscle mark not stained. Lower valve deep, not very 
thick, ribbed and fluted on the widely distended margin. Upper 
valve flat with rather broad horny scales. The lower valves 
are in nearly all my specimens coated with cemented sand or 
calcrete—at present I am disposed to refer them to 0 . Atlantica 
and to the Welsh oyster of McAndrew. 
Some shells received from Carlingford Lough are very tender 
and delicately lamellated on the upper valve, the margins and 
the valves being confluent. They belong to the group a figured 
in Miss Massy’s plate 1 , but appear to be larger examples if they 
are of the same variety, measuring 3J by 3m. in length. 
(Plate xvii., fig. 22.) 
I have also some oysters from Cullanamore, Co. Sligo, which 
I cannot place. They have a pointed ovate outline, and a 
swollen or curved upper valve. 
OSTREA CANTII sp. nov. 
I have received from Mr. A. S. Kennard, F.G.S., a number 
1 Irish Fisheries Scientific Investigation .Vo. n. 1913, ft. 11, fit’. 6 —7. 
