210 MISCELLANEOUS OBJECTIONS TO THE 



to grasp could preserve the lives of the individuals possess- 

 ing it, or favor their chance of having and of rearing off- 

 spring." But there is no necessity for any such belief. 

 Habit, and this almost implies that some benefit great or 

 small is thus derived, would in all probability suffice for the 

 work. Brehm saw the young of an African monkey (Cer- 

 copithecus) clinging to the under surface of their mother by 

 their hands, and at the same time they hooked their little 

 tails round that of their mother. Professor Henslow kept 

 in confinement some harvest mice (Mus messorius) which do 

 not possess a structurally prehensile tail ; but he frequently 

 observed that they curled their tails round the branches 

 of a bush placed in the cage, and thus aided themselves in 

 climbing. I have received an analogous account from Dr. 

 Giinther, who has seen a mouse thus suspend itself. If the 

 harvest mouse had been more strictly arboreal, it would per- 

 haps have had its tail rendered structurally prehensile, as is 

 the case with some members of the same order. Why Cer- 

 copithecus, considering its habits while young, has not become 

 thus provided, it would be difficult to say. It is, however, 

 possible that the long tail of this monkey may be of more 

 service to it as a balancing organ in making its prodigious 

 leaps, than as a prehensile organ. 



The mammary glands are common to the whole class of 

 mammals, and are indispensable for their existence ; they 

 must, therefore, have been developed at an extremely remote 

 period, and we can know nothing positively about their man- 

 ner of development. Mr. Mivart asks: "Is it conceivable 

 that the young of any animal was ever saved from destruc- 

 tion by accidentally sucking a drop of scarcely nutritious 

 fluid from an accidentally hypertrophied cutaneous gland of 

 its mother ? And even if one was so, what chance was there 

 of the perpetuation of such a variation ? " But the case is 

 not here put fairly. It is admitted by most evolutionists 

 that mammals are descended from a marsupial form ; and if 

 so, the mammary glands will have been at first developed 

 within the marsupial sack. In the case of the fish (Hippo- 

 campus) the eggs are hatched, and the young are reared for 

 a time, within a sack of this nature ; and an American natur- 

 alist, Mr. Lockwood, believes from what he has seen of the 

 development of the young, that they are nourished by a secre- 

 tion from the cutaneous glands of the sack. Now, with the 

 early progenitors of mammals, almost before they deserved 



