25^4 MISCELLANEOUS OBJECTIONS TO THE 



Cercopitheciis, 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 ita 

 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 v/e can know nothing positively about 

 their manner of development. Mr. Mivart asks: ^^Is it 

 conceivable that the young of any animal was ever saved, 

 from destruction by accidentally sucking a drop of scarcel}'' 

 nutritious fluid from an accidentally hypertrophied cuta- 

 neous 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 marsu- 

 pial form; and if so, the mammary glands will have been 

 at first developed within the marsupial sack. In the case 

 of the fish (Hippocampus) the eggs are hatched, and the 

 young are reared for a time, within a sack of this nature; 

 and an American naturalist, Mr. Lockwood, believes from 

 what he has seen of the development of the young, that 

 they are nourished by a secretion from the cutaneous 

 glands of the sack. Now, with the early progenitors of 

 mammals, almost before they deserved to be thus desig- 

 nated, is it not at least possible that the young might have 

 been similiarly nourished? And in this case, the individu- 

 als which secreted a fluid, in some degree or manner the 

 most nutritious, so as to partake of the nature of milk, 

 Avould in the long run have reared a larger number of well- 

 nourished offspring, than would the individuals which 

 secreted a poorer fluid; and thus the cutaneous glands, 

 which are the liomologues of the mammary glands, would 

 have been improved or rendered more effective. It accords 

 with the widely extended principle of specialization, that 

 the glands over a certain space of the sack should have 

 become more highly developed than the remainder; and 

 they would then have formed a breast, but at first without 

 a nipple, as we see in the Ornithorhyncus, at the base of 

 the mammalian series. Through what agency the glands 



