BRITISH OYSTERS ! OLD AND NEW. 2I<4 
Since the ioregoing was set up, I have received trom W. L. 
Calderwood, Esq., F.R.S.E., of the Fishery Board for Scotland* 
a number of examples of the older types of oyster once common 
in West Scotland, and much valuable information. The speci¬ 
mens sent me are from Jura and Loch Don in Mull, and are all 
dead shells, and they clearly bring out that the form, which I have 
called 0 . celtica, was the ancestral and predominant oyster of 
these seas, the elongated outline gradually becoming rounder 
as it passed southwards. The Jura shells are more disintegrated 
internally than are those from Mull, which have the nacreous 
lining preserved unbroken and lustrous. The existence of these 
shells in Loch Don seems to have been unnoticed till discovered 
by Mr. Calderwood, who found in the neighbourhood a series of 
stumps of branches of trees roughly pointed at the ends. As Mr. 
Calderwood found some of the shells attached to the stumps, they 
may be, to use Mr. Calderwood’s words, “ regarded as collectors 
to catch spat, as the Japanese use Bamboo ” to-day. 
Both in Jura and in Mull, other forms occur, but not so abun¬ 
dantly as do the Celtica group. Amongst those from Mull is a 
very fine example of the thick massive dark-coloured form of the 
Estuarii group, like those mentioned above (p. 204), from 
Grangemouth, Micklewood and the Nar Valley, which cannot 
be differentiated from a Dogger Bank shell in my collection, all 
being of the hippopus habit. . 
A few of the Mull shells both in size and ornament are not 
unlike one of the shells figured by the authors of the Mollusques 
Marines du Roussillon from Cancale, N.W. France (pi. i., fig. 4).. 
They are more recent than the shells I have referred to above. 
The attempts hitherto made to repopulate the oyster beds 
of W. Scotland do not appeal' to have been very successful* 
whether in Shetland, or farther south, as at Arisaig in South 
Invernesshire, where stock from Colchester, in Essex, was 
laid down, or at Loch Sween, Argyleshire, where a large con¬ 
signment from Arcachon, S. of Bordeaux, was utilised. Pro¬ 
bably in these latter instances the climate was too strong for the 
strains selected. The Loch Sween shell figured (pi. xvii., fig. 
23), may have been introduced with the Arcachon shells. 
The most recent of the Mull and Jura shells are of the 
“ Pandoure type ” (plate xiii., fig. 6), and appear to be of no great 
age from their condition, a portion of the adductor muscle still 
