MAKSUPIAL GENEKATION. 823 



relative to the generation of these creatures *. The annexed figure 

 (fig. 415) is a portrait of one of the specimens dissected ; and from every 

 appearance it could not have been more than a few days old that is, 

 supposing it to have been born at an advanced period of its development. 

 It was as yet blind ; and the situation of the eyes was only indicated by 

 the convergence of a few wrinkles to one point ; but when these were 

 put upon the stretch, the integument was found entire, and completely 

 shrouding or covering the eyeball anteriorly : its skeleton, moreover, was 

 quite in a cartilaginous condition ; and it was obviously in every respect 

 helpless, and still dependent upon its mother for sustenance. 



(2430.) The stomach was found filled with milk a sufficient proof 

 that at that period, at least, it was nourished by the lacteal secretion ; 

 but with regard to its previous foetal condition, the difficulties that have 

 been above alluded to remained in their full force. No trace of an 

 umbilical cicatrix was visible upon the ventral surface of the body, even 

 when examined with a lens, a sure proof that no placenta had existed. 

 The ilium was carefully examined, but there was no appearance of the 

 pedicle of the vitelline vesicle ; nevertheless the other vestiges of foatal 

 organization were more obvious than in the ordinary marsupial or ovo- 

 viviparous Mammalia. The umbilical vein was seen extending from a 

 linear cicatrix of the peritoneum, opposite the middle of the abdomen, 

 along the anterior margin of the suspensory ligament to the liver. It 

 was reduced to a mere filamentary tube filled with coagulum. From the 

 same cicatrix the remains of the umbilical arteries extended downwards, 

 and near the urinary bladder were contained within a duplicature of 

 peritoneum, having between them a small flat oval vesicle, the remains 

 of an allantois, which was attached by a contracted pedicle to the fundus 

 of the bladder ; but still, as both the embryo of the Bird and that of the 

 ovo viviparous Eeptile have an allantois and umbilical vessels developed, 

 no certain inference can be drawn from the above appearances as to the 

 oviparous or viviparous nature of the generation of the Ornithorhynchus. 



(2431.) Such is the present state of our knowledge relative to the 

 first type of Mammiferous generation, viz. that met with among the 

 MONOTREMATA. In the second, or MARSUPIAL TYPE, the phenomena, 

 although equally strange, are better understood ; and to these we must 

 now beg the attention of the student. 



(2432.) The MARSUPIILIA, from the variety of their forms and exten- 

 sive distribution, constitute a most important section of Mammiferous 

 quadrupeds, distinguished by the peculiarities that occur in the organi- 

 zation of their generative apparatus and by the singular mode in which 

 they produce and suckle their young. Animals of this kind are only 

 met with in the American and Australian regions of our globe ; and so 

 widely do they differ, as far as their reproduction is concerned, from all 

 the Mammiferous inhabitants of the Old World, that they might even be 



* Owen on the Young of the Ornithorhynchus paradoxus, Trans. Zool. Soc. vol. i. 



