326 Prof. Owen on the Reproduction of the Opossum. 



" Two lungs, each consisting of minute transparent vesicles re- 

 sembling small soap-bubbles. 



" Such is the anatomy of the young opossum of three and a half 

 grains, destined to attain a weight of fifteen or sixteen pounds. 



" While lying on the watch-glass, I put the smooth point of a pencil 

 to its stomal pore. The animal sucked at the pencil, and held on so 

 firmly, that I could lift it partly off the glass by it. 



" Does this fact show that twenty-four hours earlier it could draw 

 the delicate teat into the orifice ? 



" The young, having the teat once in the mouth, cannot let it go; 

 nor does it abandon it for many days. 



" I could discover no trace of an umbilicus. I sought for it with 

 a good doublet. But it is not to be believed that a breathing, san- 

 guiferous, digesting mammifer can be developed independently of a 

 placenta. 



" On Monday March 12th, an animal being removed for dissection 

 weighed twelve grains ; it breathed thirty- two times per minute. 



" March 18th. A young one weighed eighteen grains. The tail 

 very prehensile. 



" I immersed it in a cup of alcohol to kill it for dissection. It did 

 not die in the fluid until it had been immersed in it for sixteen 

 minutes. 



" The observations show the marsupial young to have a chylopoietic, 

 warm-blooded, oxidating, innervating, and free-willing life, being as 

 fully endowed with all the means of an independent existence, as the 

 young of the elephant at the teat. 



f If this be so, all mystery as to the nature of the life of the mar- 

 supial young is at an end." 



With regard to the statement, that I omitted to " mention the 

 preliminary condition of the mammary glands in the Kangaroo/ 7 

 I beg to refer to my article Marsupialia, ' Cyclopaedia of Ana- 

 tomy/ t. iii. p. 321, where, in reference to the female kangaroo 

 experimented on, I state, — " The right superior nipple was the 

 one in use ; it was nearly two inches long and one-third of an 

 inch in diameter ; the mammary gland formed a large swelling 

 at its base. The other three nipples were everted and about half 

 an inch in length." — "Sept. 11th, fifteenth day of gestation, 

 nipples in the same condition." — " Sept. 30th, thirty-fourth day, 

 the nipple in use by the young kangaroo (which has died) is 

 diminished in size." And again : " Oct. 4th, the nipple formerly 

 in use has diminished one-third in size ; the other nipples indicate 

 no appearance of approaching parturition." The following day 

 (thirty-ninth of gestation) " the new-born kangaroo was in the 

 pouch and attached to the left superior nipple." Having specified 

 the particular mammary gland which was enlarged, I presumed it 

 would be understood that the others were not enlarged, and 

 formed no swelling at the base of the smaller nipples. 



The phamomena observed and described by Dr. Meigs are 



