426 Analytical Notices of Books. 



he covered the whole with snow, and in this manner constructed 

 a wall which occupied two thirds of the door-way. During the 

 night the snow was frozen, and in the morning the results of the 

 Beaver's labours were discovered, the animal having deprived 

 itself of its customary food for the purpose of procuring itself 

 shelter against the inclemency of the weather. 



The Memoir of M. Isidore GeofFroy Saint-Hilaire is, '' On 

 Female Pheasants possessing the plumage of Males." He recals 

 the fact noticed by Vicq d'Azyr and Mauduit, of the aged fe- 

 male of the common Pheasant (^Phasianus Colchicus,) acquiring 

 occasionally a plumage differing from that of the male only in its 

 colours being less vivid ; and then proceeds to detail two in- 

 stances of a similar kind which have fallen under his own observa- 

 tion. In the first of these a female of the common Pheasant 

 ceased laying eggs at the age of five years. From that period her 

 plumage begau to change, at first on the abdomen, which be- 

 came more yellow, and on the throat, the colours of Avhich were 

 more vivid, and shortly after on the whole of the body. In the 

 following year the tints of the plumage assumed still more the 

 brilliancy of that of the male ; and these became so decided in 

 the third year that it was almost impossible, by the mere inspec- 

 tion of its colours, not to be mistaken in its sex. Her habits 

 changed with her plumage j she became careless of the society of 

 the males, to whom she was equally an object of indifference. 

 At this epoch she died. In the second instance the resemblance 

 became still more complete. A female of the Phasianus nycihe- 

 merus had ceased laying for three or four years, and had reached 

 the age of eight or ten, when a mixture of white feathers among 

 the usual brownish ones announced the commencement of the 

 change of her plumage to the colours of the male. This change 

 became more strongly marked in the next year, and in the third 

 year it was complete. In the fourth, she assumed entirely the 

 appearance of the male, the crest and tail becoming elongated, 

 and the change thus affecting not merely the colours, but also the 

 relative proportions of the feathers. In the fifth year the re- 

 semblance might be termed identical ; she represented a male in 

 his most brilliant state of plumage. Shortly after this period she 



