MR. OWEN ON THE GENERATION OF THE MARSUPIAL ANIMALS. 335 



Blmnville* and Morgan -l^, have more especially been devoted to its elucidation ; but 

 the attainment of a precise knowledge of the mode in which the embryo was deve- 

 loped, — the more desirable on account of the abovementioned affinities of the Marsu- 

 piata to the Ovipara, — has been prevented by the want of opportunities to examine 

 the impregnated uterus, so as to determine the nature of the relations subsisting be- 

 tween the foetus and mother. 



This deficiency I have the good fortune to be in some degree enabled to supply 

 through the exertions of my friend Mr. George Bennett, F.L.S., who during his 

 recent travels in New South Wales procured the gravid uterus of a female of the 

 large Kangaroo (Macropus major, Shaw), and safely transmitted it in spirits to the 

 Museum of the Royal College of Surgeons in London, where it is now preserved, and 

 where I have had the opportunity of examining it for the present communication, 

 through the liberal permission of the President and Board of Curators. 



The foetus was contained in the left uterus (Plate VI. fig. 7- c'.), which was three times 

 the diameter of the same part in the unimpregnated state. This uterus measured two 

 inches in length and one inch three lines in diameter, exclusive of the Fallopian tubes. 

 Its parietes varied in thickness from one line to two lines, being in the unimpregnated 

 state about half a line ; and this increase was not in the muscular coat, but was 

 chiefly occasioned by the thickening of the internal membrane, which was produced 

 into irregular folds and wrinkles, having, however, a smooth surface when put upon 

 the stretch, and closely resembling the same part in the uterus of the Ornithorhynchus 

 paradoxus. 



The foetus had been exposed by a longitudinal incision through the coats of the 

 uterus, and a corresponding one in the most exterior of its envelopes, but had not ap- 

 parently been otherwise disturbed. It was bent upon itself in the usual manner, with 

 the nose almost touching the thick stem of the embryonic membranes, or umbilical 

 chord. Its whole length in a straight line was seven lines, but when measured along 

 the curve of the back to the extremity of the tail, its length was one inch four lines ; 

 the length of the head three and a half lines. 



The examination into the nature of the connexion between the mother and foetus 

 was made in presence of Mr. Clift, for whose kind and valuable assistance I am 

 much indebted. 



The edges of the uterus where it had been cut open by Mr. Bennett were care- 

 fully examined with the lens, whilst immersed in clear spirit, but no trace of a divided 

 placenta could be detected ; the pulpy projections from these edges were satisfactorily 

 seen to be folds of the lining membrane. The only point to which the foetal mem- 

 branes seemed to adhere was near the cut margin of the uterus on the right side, but 

 this was found to arise from insinuation of the chorion between folds of the lining 



* " Sur les Organes femelles de la G^ndration et les Foetus des Animaux didelphes ;" Bulletin de la Soci^t^ 

 Philomathique, 1818, p. 25. 



t Transactions of the Linnean Society, vol. xvi. pp. 61, 455. 



2x2 



