166 



mash their skull, leaving them for dead, you may come in an hour after, 

 and they will be gone quite away." 



This gemmiparous theory of Lawson that the "female doubtless breeds 

 her young at her teats," illustrates the superficial nature of the first 

 observations on Marsupial reproduction. 



Early authors — among them Pennant — contended that "the pouch 

 was the matrix of the young Opossum, and that the mammse are, with 

 regard to the young, what stalks are to the fruit." 



De Blainville speaks of two sorts of g€«tation, one uterine, the other 

 mammary. 



In 1819 Geoffrey St. Hillaire inquired of naturalists : "Are the pouched 

 animals born attached to the teats of the mothers?" 



Gcdman, in 1826, adniits, in his otherwise complete history of the an- 

 imal, that " the peculiarities of its sexual intercourse, gestation, and par- 

 turition, are to this day involved in profound obscurity." 



DeKay, in 1842, states : " The young are found in the external abdom- 

 inal sac, firmly attached to a teat in the form of a small gelatinous body 

 not weighing more than a grain." 



This was nine years after Owens' observations on the development 

 of the Great Kangaroo. DeKay, however, simply quoted such natural 

 history literature as was nearest to hand; and, as is remarked in the 

 Bibliography of North American Mammals (Gill & Coues), DeKay's 

 Fauna of New York "has not been recognized as of high authority, nor 

 has it exercised much influence upon the progress of science." 



It was loag believed that there existed a direct passage from the uterus 

 to the teat, but this, of course, was disproved by dissection. Another 

 opinion was that the embryo was formed where first found. 



It is at once seen that the tacts regarding the reproduction of this 

 comm(jn animal have been developed very slowly, and not until Owen 

 gave an exact description of the corresponding organs in the Kangaroo 

 and discovered the foetus in utero, could naturalists conclude the discus- 

 sion of reproduction in the Opossum, ' 



Audubon and Bachman attempted for several years to secure gravid 

 females, but were baffled, as also were various French and English nat- 

 uralists, by the fact that the Opossum does not breed in confinement. 

 Another difficulty was that the females retire to their burrows during 

 the period of utero-gestation, which, in North Carolina, the seat of 

 Audubon's observations, is about the last of February and first week 

 of March Of thirty-five taken at that time (1847), in three successive 

 nights, there was not a single female; but a week later, when the young 

 were in the pouches, more females were taken than males. In February, 



