. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 328 MARSUPIALIA. Fig. 143;. Female Didelphys dorsigera, with young and pouch. In the Kangaroos and Potoroos, which have the shortest uteri and longest vaginal tubes and cul-de-sac, the marsupial pouch is wide and deep. It is composed of a duplicature of the integument, of which the external fold is sup- ported by longitudinal fasciculi of the panni- culus carnosus converging below to be im- planted in the symphysis pubis. The mouth of the sac is closed by a strong cutaneous sphincter muscle. The interior of the pouch is
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 328 MARSUPIALIA. Fig. 143;. Female Didelphys dorsigera, with young and pouch. In the Kangaroos and Potoroos, which have the shortest uteri and longest vaginal tubes and cul-de-sac, the marsupial pouch is wide and deep. It is composed of a duplicature of the integument, of which the external fold is sup- ported by longitudinal fasciculi of the panni- culus carnosus converging below to be im- planted in the symphysis pubis. The mouth of the sac is closed by a strong cutaneous sphincter muscle. The interior of the pouch is almost naked : a few hairs grow around the nipple: it is lubricated by a brown sebaceous secretion. The mouth of the pouch is directed forwards in most Marsupials: the reversed position in the Perameles and Chaeropus, where the mouth is directed towards the vulva, has been already noticed. M. Laurent* has made the interesting observation of the presence of a rudimental pouch in the male mammary foetus of an Opossum : he could not discern equal traces of the nipples: that of the pouch is * Annales d'Anatomie et de Physiologic, 1839, p. 237. soon obliterated, as the scrotum increases in size. In the male Thylacine the rudimental mar- supium is retained, in the form of a broad triangular depression or shallow inverted fold of the abdominal integument, from the middle of which the peduncle of the scrotum is con- tinued. In the female the orifice of the capa- cious pouch is situated nearer the posterior thaa the anterior boundary of that receptacle. A few observations on the claims of the Mar- supialia to be regarded as a natural group of ani- mals may not inappropriately conclude this ar- ticle. Cuvier, in 1816, first separated the mar- supial from the other unguiculate quadrupeds, to form a distinct group, which he describes as forming, with the Monotremes, a small collateral chain, all the genera of which, while they are connected together by the peculiarities of the generative
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