On an apparently New Form of Holothuria. 
331 
In tlie coldest weather, the top or roof of the lodge is always moist or wet, 
while the sides are frozen, at least outwardly. It is certain that he can 
remain under the water for half an hour at a time. He lives in the same 
lodge for two or four years, when, finding his food scarce, he removes to 
another locality, and builds as before. 
For instinct or intelligence he is at the head of the wild animals in this 
country, and lives longer, I believe, than any of them. Other animals, 
as for instance the young of the American hare or rabbit, the marten and 
lynx, perish by thousands in the spring, either by cold, or in seasons of high 
water, or from lack of their ordinary food ; but it is all the same to the 
beaver whether the season be wet or dry, hot or cold — the shores of every 
lake and the banks of every river furnish him with abundance of food. 
I do not know whether he will thrive in Britain ; at any rate, the Zoolo- 
gical Gardens is not the best place for him ; he is fond of solitude, and 
does not like company. An island with a large lake would be the most 
eligible place for him, where, if set at large, he would soon shift for him- 
self. Of course, his usual food would require to be found on the spot. 
Dr J. A. Smith said, with regard to Mr M'Kenzie's statement that he 
could discover no air-holes in the lodges of the beaver, and wondered 
how they managed to do without air ; it was probable the air got 
access through the comparatively looser structure of the top of the lodge, 
which Mr M'Kenzie states is always moist or wet even in the coldest 
weather, while the sides are frozen outwardly. 
II. On an apparently New Form of Holothuria. By John Anderson, 
M.D. Plate XVI. 
In the autumn of 1859 I dredged, from 5 fathoms of water 
in Bressay Sound, Shetland, the Holotliuria which forms the 
subject of this memoir (Plate XYI. fig. 1). It was clinging 
to the inside of a dead and half-open Modiola vulgaris. When 
captured, it was of a cream-colour, slightly speckled with 
brown; but since it has been in confinement, it has sensibly 
deepened in colour. During the first months of its imprison- 
ment it was very lively, especially at night ; during the day, 
when exposed to the light, it always contracted itself into a 
little ball, confining itself to one spot, and that the one ex- 
posed to sun-light. The tentacles were always exposed at 
night, but were immediately retracted whenever any attempt 
was made to examine them. About the beginning of the 
second month of its confinement it became more sluggish, 
and remained for days contracted, never displaying its ten- 
tacles even at night. The body contracted so firmly upon 
itself, that many of the feet by which it was attached gave 
way, and were left sticking to the sides of the glass vessel in 
which it was confined. After remaining in this condition 
for some time, the integument about the centre of the body 
