INTRODUCTION. 9 



and still more when they afterwards return to the 

 pouch for temporary shelter/'* The author next 

 proceeds to point out the uses of these bones in the 

 males, which, I may observe, have peculiarities cor- 

 responding to the pouch in the female.t 



It is in the Mammalia that the brain is perfected ; 

 " we can trace through the different orders the 

 increasing complication of this organ, until we find it 

 in man to have attained that condition which so 

 eminently distinguishes him from the rest of the 

 class. And if the introduction of new powers into 

 an organism, necessarily requires a modification in 

 its mode of development, with what other than the 

 perfection of the nervous system can we connect true 

 viviparous or placental generation ? for we do not 

 perceive that in their digestion, circulation, respira- 

 tion, locomotion, or temperature, the mammiferous 

 vertebrata are in any degree advanced beyond the 

 bird, in consequence of their more complex, or, as it 

 may be termed, more careful generation. "J 



Agreeably to this view, connected with the ovovi- 

 viparous generation of the Marsupiata, and with an 

 inferiority of intelligence, which Professor Owen ob- 

 served in these animals when in confinement, he was 

 induced to undertake a careful examination of the 



* Philosophical Transactions for 1 834, p. 333. 



f- Ad characteres supra dictos addantur in maribus situs 

 testium ante penem, et in feminis vagina in duas canales septo 

 divisa. 



+ Owen in Phil. Trans. 1834, p. 359. 



