INTEODUCTOEY. 29 



than the lion whelp. The young of deer that are uniformly 

 coloured when adult are also, in some species, distinc.tly 

 spotted when young. 



On the theory that every colour change has a meaning in 

 relation to the needs of the individual, it is not easy to see why 

 animals that are of a uniform colour should commence life by 

 being spotted. It has been suggested that the spots on the 

 young — in the case of the Carnivora, at any rate — enable their 

 parents to recognise them in the semi-obscurity of the caverns 

 or dark places which they inhabit ; but it is not likely that an 

 explanation of this kind can apply to all the cases mentioned. 



It might, however, with some reason, be urged that the defini- 

 tive coloration is soon acquired ; and that in consequence the 

 ex hypothesi) disadvantageous colours of the young would not 

 have time to do their possessors much harm. 



But even this way out of the difficulty is barred in the case 

 of Gulls. 



The bluish and white colour of many gulls is generally 

 allowed to be of protective value ; in any case, they are not 

 unlike their usual surroundings. For three years several of the 

 common species of gulls have a brownish speckled plumage, 

 which is totally unlike that of the old bird ; if one colour 

 is advantageous, the other must be the reverse ; and three 

 years is either a considerable period, or not long enough. 



The fact of the matter is that the colours of the young in 

 these cases are to be probably explained as a recapitula- 

 tion of ancestral characters, as in the case of the cater- 

 pillars investigated by Weismann. It is agreed among all 

 Ornithologists, since Professor Huxley's well-known paper 

 upon the " Classification of Birds,"* that the gulls are 

 most nearly related to some of the Waders. Now, a brownish. 

 * Proc. Zool. Soc, 1867. 



