194 
Part III. — ISinth Annual Report 
face temperature of the outside water, which was about 2 fathoms deep. 
This is interesting, as showing that with shallow ponds it would be 
possible to raise by solar heat the temperature of the water, and that, too, 
while a constant interchange — slow no doubt — was taking place between 
the sea-water inside and that outside of the separating wall. If, at the same 
time, with the rise of temperature which would undoubtedly favour the 
development of the eggs and embryos, arrangements were made for 
retaining the pelagic and fixed forms in water warmer than the surround- 
ing sea, a great step in advance would be taken towards the rearing of a 
greater quantity of spat in our own waters. In good years, both in 
France and Holland, more spat is obtained by ostreiculturists than they 
can fatten on their beds. Their superabundance, if transferred to such 
Scottish waters as West Loch Tarbert and other suitable fattening grounds, 
would develope a new industry of a most promising character as regards 
financial returns. 
On Messrs Hay's natural oyster-bed oysters of one, two, three, and four 
years of age were obtained, of a diameter of from 4J inches downwards. 
Below this bed, on the east side of Corran among the Zostera marina, 
many young and half-grown oysters were dredged from the >shelly sand. 
Xaturally this is a good place for the fixation of tlie spat. Large numbers 
were obtained on old oyster shells, on living oysters, and even on stones of 
micaceous schist. On one Cardium shell there were a score in a cluster 
J to 1 J inches in diameter. Shells of Venus, Madra, Anomia, and pieces 
of tile were also covered with young and vigorous oysters. The quantities 
of Anomia found in West Loch Tarbert were much less tlian in Loch 
Ryan. 
Amongst all the oysters in West Loch Tarbert one noticeable and 
favourable feature was the great development of periostracum (the 
outer chitinous covering of the shell). This showed the rapid growth or 
progress, and also what was likely to be exhibited during the latter part 
of the year. Up till the date of my visit in July all the oysters showed 
good growth for 1890. To the oysters were attached Ascidia ynentula, 
Mytilus eduUs, Serpulce, and tubicolous worms and barnacles ; and amongst 
the zoophytes sucli forms as Hjidralhnannia, Bugula, Antennularia, and 
Membranipora were attached to the oyster shells. 
Not only were the shells large, but the cubical capacity of the contained 
cavity between the valves was great, and the oysters were fat and well 
filled. Here, as at Loch Ryan, oysters were found containing spat. In 
Loch Ryan the proportion was smaller, and the spat was chiefly in the 
early segmentation stage (white spat) ; but in West Loch Tarbert the 
spat was chiefly black spat, showing that the oysters in this Loch were in 
a much more forward reproductive state than those in Loch Ryan. In 
many the young were nearly ready to leave the mother, the shell-valves 
being large and covering the organs of the larva. 
While Messrs Hay & Co. are conducting their operations in an 
intelligent manner, there is still room for a further development on the 
uncultivated and unappropriated portion of the loch. 
2. Following the lochs where oyster culture has been attempted, there 
remain for treatment those in which no culture has been attempted. 
Among these it m ly be convenient to deal with Loch Swen, for which an 
oyster order has been granted in favour of Colonel Malcolm of Pollalloch 
and Captain Campbell of Inverneil. 
In Loch Swen proper I did not obtain any oysters, but in that branch 
of it known as Liune ]\Ihuirich oysters occurred in great plenty. Opposite 
Taynish House on every stone which was lifted one to a dozen oysters 
were found. At low water these stones, in water not over 18 inches 
