BOOK NOTICES. 105 



D 



111 Hie "Fauna of British India" the restriction of space necessarily submitted to 

 by Mr. Dates has rendered his work less full of details than Jerdon's ; but the 

 publication of the present volumes supplies the deficiency in great part, as most 

 interesting details' of the habits, &c, of the species are given. As an example of 

 the readable manner in which scientific information can be conveyed, the following 

 extract which bears strongly on the questions recently raised in our columns on the 

 breeding of polygamous birds is most interesting. Writing of the King Crow, or 

 Black Drongo, Dccruris ater, Mr. Hume says : — 



" Of this bird we have already taken during the last six weeks at least fifty nests, 

 and in many cases where we had left the empty nest in statu quo, we found it a 

 week later with a fresh batch of eggs laid therein. Many birds will never return 

 to a nest which has once been robbed, but the others, like the King Crow and the 

 Little Shrike {Lanius rillatns), will continue laying even after the nest has been 

 cleared of perhaps four slightly incubated eggs ; a fresh one that otherwise would 

 assuredly never have seen the light is laid, and that, too, a fertile egg, which, if not 

 meddled with, will be hatched off indue course. It might be supposed that, imme- 

 diately on discovering their loss, nature urged the birds to new intercourse, the 

 result of which was the fertile egg, and this in some cases is probably really the 

 case, martins and others of the swallow kind being often to be seen busy with 

 ' love's pleasing labour' before their eggs have been well stowed away by the 

 collector. But this will not account for instances that I have observed of birds 

 in confinement, who separated from the male before they have laid the full num- 

 ber, and then later, just when they began to sit, deprived of their eggs, straight- 

 wav laid a second set, neither so large nor so well coloured as the first, but still 

 fertile eggs that were duly hatched. But for the removal of the first set these 

 subsequent eggs would never have been developed or laid. Now the theory has 

 always been that the contact of the sperm and germ cells causes the development 

 and fertilization of the latter. In these cases no fresh accession of sperm cells 

 was possible, and hence it would seem as if in some birds the female organs 

 were able to store up living sperm cells, which only work to fertilize and develope 

 ova in the event of some accident rendering it necessary, and which otherwise 

 ultimately lose vitality and pass away without action." 



Regarding the vexed question as to whether birds ever leave their eggs to be 

 batched by the heat of the sun, Mr. Hume has some very interesting experience 

 to relate. Writing of the common Myna (Acridotheres tristis), Mr. Hume 

 described the building of a nest in a hole in a wall of his verandah, stating that the 

 pair seemed present at all hours of the day. He then goes on to state : 



" I made certain that they had not even begun to sit, and behold, there were four 

 fine young ones, a full week old, chirping in the nest ! Clearly these birds are not 

 close sitters down here ; but I well remember a pair at Mussoorie, some 6,000 feet 

 above the level of the sea, the most exemplary parents, one or other being on 

 the eggs at all hours of the day and night. The morning's sun beats full upon 

 the wall, in the inner side of which the entrance to the nest is ; the nest itself is 

 14 



