On an apparently New Form of Holothuria. 331 



In the 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 o f 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 Holothuria which forms the 

 subject of this memoir (Plate XVI. 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 



