Notices of New Books. 4267 



We need only allude to one of these papers, that by Mr. Hancock. 

 This ornithologist published an opinion that two very similar species 

 of Falco were, by many naturalists, included under the name of Falco 

 Islandicus ; these are characterised as the Greenland falcon {Falco 

 Groznlandicus) , and the Iceland falcon [Falco Islandicus) : both of 

 them are usually included by English ornithologists under the name 

 of gyr falcon or jerfalcon. In 1838, Mr. Hancock entered fully into 

 the question of plumage, as far as he was then able to decide on such 

 differences as age, sex, season, and casual aberration might be sup- 

 posed to produce. Whether his conclusions were drawn from true 

 premises at that time, the following passage in the present paper will 

 show : — 



" When I drew up my paper, I considered all the white birds from 

 Greenland to be mature, describing the nest-plumage from a dark 

 specimen, which, having a white quill-feather coming, seemed to 

 prove that it was the young of this species. There is now no doubt 

 that this is wrong, and that this individual is really an immature Ice- 

 land falcon, the white quill-feather being abnormal." — P. 110. 



Nothing daunted by this error, thus honourably acknowledged, Mr. 

 Hancock's general conclusions are the same now as in 1838 ; but he 

 closes his paper with a paragraph that somewhat startles us : — 



" In conclusion, it may be stated that the characters of the two 

 forms are permanent and sharply defined, never blending into each 

 other ; and that the young, as well as the mature birds, can always be 

 distinguished. But whether these two falcons are to be considered 

 distinct species or mere races, must depend upon the views enter- 

 tained regarding what is to constitute specific character." — P. 112. 



So that after all the pains which the author has taken ; after he has 

 imposed names and defined characters ; after he has positively stated 

 that the characters are permanent and never blending ; and that indi- 

 viduals, young or old, may always be distinguished, we are told that 

 the reception of the two as species, is to depend on our own option 

 in settling w T hat a species really is. 



Birds of Paradise in confinement. — "A rich colonist at Batavia 

 kept a number of rare birds in confinement, and amongst them several 

 pairs of birds of Paradise. A captain who visited this colonist was 

 much struck with the way in which the /males displayed themselves 

 before the females. By means of a sort of vibration of their entire 

 plumage, they raised all the feathers, including their long plumes, and 

 surrounded themselves completely, so as to form a sort of halo, in the 

 centre of which the bright green head formed a disk, which at the 



