114 THE ZOOLOGIST. 
By imitating one of his prominent calls the hunter can lure him within 
gun-shot, although naturally very shy ; he comes to repel a fancied intruder 
into his domain. His flesh is very dark-coloured and coarse, and only used 
as food in cases of necessity. Many attempts have been made to rear the 
birds in captivity, and there is a report that one has been successful. With 
this exception, which I cannot authenticate, I never heard of any result but 
failure. The sound of his call so alters in proportion as his tail is in full 
feather or indifferently ornamented, that hunters can judge from that 
whether or no any individual bird is worth pursuit. My apology for asking 
for so much of your valuable space must be in the fact that, until I set 
myself the task of getting the above information I could not obtain it from 
published accounts, — AtrreD Morris (Railway Survey Camp, Manaro, 
New South Wales), in ‘ Nature.’ 
FISHES. 
Porbeagle Shark at Plymouth.—On the 26th January last I examined 
a fine male Porbeagle Shark, Squalus cornubicus, eight feet in length, which 
had been taken in a herring-net off Plymouth. Its eyes were large, and 
almost round, the irides dark, with a small oblong spot of emerald, or bright 
pea-green, in the centre of the pupils. This species is far less frequently 
captured by the Plymouth fishermen than the Blue Shark, Squalus glaucus, 
which has been rather plentiful on the coasts of Devon and Cornwall during 
the last few years.—J. GatcomBE (Durnford Street, Stonehouse). 
MOLLUSCA. 
The resting position of Oysters.—I observe in the last number of 
‘The Zoologist’ (p. 79) that Mr. J. T. Cunningham has revived the question 
as to the natural position of the Oyster in its bed. He is right in his opinion 
that these bivalves usually lie with the left, or convex, valve wppermost. 
Prof. Huxley and other authorities are also correct in the statement that 
the shell is invariably attached by the convex valve. The discrepancy is 
explained by the fact that most Oysters in their first or second year become 
detached from the substance to which they fastened themselves in their 
infancy. This is effected either by the “ cultick-knife” of the dredger, who 
makes it his business to separate the young brood from the stone or shell 
to which it is found adhering; or, more frequently, by natural means, as, 
the “spat” being generally deposited in clusters, the individual Oysters 
grow against each other, and the shells are thus forced upwards from the 
surface of attachment and ultimately broken off. To facilitate this operation 
the tiles used in artificial breeding-grounds for the collection of the spat are 
coated with a friable cement. If the free Oyster falls on the convex shell it 
soon becomes turned over by the motion of the water, and then remains 
