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Proceedings of the Royal Society 
many dry seasons: and notably in 1863 there was a very long- 
continued drought, proving so destructive to the salmon at Grimasto 
that it was said some 1500 fish were picked up dead on the shores 
of the hay and mouth of the riveT. I and my friends were not in 
the Lewis that year, and therefore I cannot speak as to the symp- 
toms of that disease; but inquiry afterwards failed to elicit any 
evidence that they resembled "the outbreak of 1868. ... It may 
be that the fish in 1868 were in some' peculiar abnormal condition 
before coming up from the sea , predisposing them to disease of the 
head; but at any rate I can give no other cause for the outbreak 
than those I have mentioned/’ 
3. On the Form and Structure of the Teeth of Mesoplodon 
Layardii and Mesoplodon Sowerbyii. By Professor Turner, 
M.B. 
The author in the first instance described the characters of the 
teeth of Mesoplodon Layardii from two specimens which had been 
collected during the expedition of H.M.S. “Challenger,” under the 
scientific superintendence of Sir C. Wyville Thomson. The one 
specimen, a young animal, under 14 feet in length, was obtained 
at Port Sussex, East Falkland Islands, by Mr H. H. Moseley, 
F.RS. ; the other, an adult skull, was procured at the Cape of 
Good Hope. 
The teeth of the younger animal, two in number, were imbedded 
in their alveoli in the lower jaw. Each tooth consisted of a small 
triangular denticle or crown projecting outwards, and slightly 
upwards from the middle of the upper border of the fang. The 
denticle measured 4-10ths inchin its longer diameter, the fang was 
2 inches by 8-10ths. At the base of the fang was a cleft 2-10ths 
inch wide, which communicated with a pulp cavity that was pro- 
longed almost to the apex of the denticle. 
The denticle was invested by enamel, subjacent to which was 
a well-defined mass of dentine, which was prolonged as a thin 
layer almost down to the cleft at the root of the fang. The fang 
was invested by cement, which was separated from the dentine 
