300 Notice regardinty a specimen of' Sirtn liicertlna 



delicate fimbriae at their extremities. We thought that we ob- 

 served in the animal a preference for pure water, as it regularly 

 became more lively as often as the water was changed ; and we 

 found by experience that any floating foliage that served to hide 

 or cover it, was highly agreeable to its dispositions. We there- 

 fore at last adopted the plan of keeping a large patch of frog- 

 bit (Hydrocharis morsus ranae) constantly vegetating on the 

 surface. This tended also to keep the water from corrupting. 

 When this floating patch was slowly moved from side to side 

 of the reservoir, the siren kept most accurately beneath it, en- 

 deavouring to avoid observation ; and in this exercise it shewed 

 great alertness and sagacity. 



On the morning of the 22d October 1831, the siren was found 

 by the gardener lying dead on the paved footpath of the hot- 

 house, not far from the reservoir. It did not appear to have 

 met with any injury in its fall from the reservoir, which was 

 placed on a trclhs about three feet above the pathway. The fall 

 indeed must have been broken by intervening flower-pots, and no 

 external marks of lesion appeared on the body. The fine fim- 

 briae of the branchial apparatus, however, were completely dried 

 and shrivelled up ; and I have no doubt in my own mind that 

 the death of the animal arose from this cause. The older natu- 

 ralists supposed these fimbriae or fringes to be opercula or gill- 

 covers, and regarded the vertical clefts or perforations in front 

 of the fringes as the true gills ; but Mr Wilson is certainly 

 right in considering the fringes as the true gills. 



In the New York Medical and Physical Journal for June 1824, 

 Dr Samuel L. Mitchell gives an account of the examination of 

 several specimens, dead and alive, which had been transmitted to 

 New York by the same Dr Farmer of Charleston who sent the 

 living specimen to Edinburgh. Dr Mitchell seems to think it 

 most probable that the air-sacs, called lungs, do not perform 

 any direct respiratory function, but are mere receptacles of air, 

 performing only an auxiliary service, in occasionally furnishing 

 the branchiae or gills with the atmospheric air which the animal 

 from time to time inhales, and which is detained in these recepta- 

 cles till wanted. I cannot help thinking that this view acquires 

 additional probability from the circumstance of the Canonmills 



