106 Proceedings of the Royal Society of Victoria. 



Chaeropus/ we find the typical marsupial ai'raiigement of two 

 external iliac arteries arising from the abdominal aorta, which 

 continues posteriorly as a common iliac trunk, ending in. the 

 median sacral artery. In Didelphys virginiana," and in Ves- 

 perugo noctula,^ and Ornithorhynehus,^ we rind an arrangement 

 somewhat similar to that of Notoryctes, the internal iliac arteries 

 coming off from the external iliac trunks. This also is found in 

 the higher Mammals, of which the Rabbit and also Man may be 

 given as examples. In many Marsupials, and also in some of 

 the higher Mammals, e.^s^:, the Rabbit, there seem to be, so far as 

 I can tind to the contrary, a common internal iliac vein receiving 

 an internal iliac branch on the right and left, and a median 

 sacral vein ; thus in some specimens of Didelphys virginiana, 

 McClure^ finds this type, and also Hochstetter^ in his series of 

 Marsupial forms. In one species of Halmaturus, however, H. 

 bennetti, Hochstetter finds a bifurcation of the postcaval vein into 

 the two common iliac trunks, which are formed in turn by inter- 

 nal and external iliac veins, the common iliac receiving on the 

 left side a median sacral vein. In some specimens of Didelphys 

 virginiana," McClure finds an approach to the Notoryctes type 

 of internal iliac vein. Owen,* moreover, records a closely similar 

 arrangement in the Ant-eaters and Armadilloes, and in some 

 species of Bradypus. Each of these only differs from Notoryctes 

 in that the latter has no median sacral vein, probably because 

 of the small size of the tail, or the large size of the lateral sacral 

 vessels. Except in Didelphys, in each of the Marsupial cases, so 

 far as I can find any record, the arteries conform to the usual 

 Marsupial type. 



Cofic/usion. 



If, with Owen,** we are to regard the state of development of 

 the internal iliac vessels, especially the arteries, as a criterion 



1 Parsons : Jour. Linn. Soc. Lend., vol. xxix., 1903, p. (54. 



2 McClure: Anat. Anz., 18, p. 444. 



3 Hochstetter: Morphol. Jabrbuch., x.\. bd. 4, Heft., p. 625. 



4 Owen : Couip. Anatomy of Vertebrates, vol. iii., p. 53S, .i40-l. 



5 McClure : Anat. Anzeiger, IS, p. 444. 



6 Hochstetter: Moi-phol. Jabrbuch, xx. bd. 4. Heft., p. 626. 



7 McClure . Anat, .\iizeiger, IS, Figs. 4, S, 15, 16. 



8 Owen: C'onip. Anat. of Vertebrates, vol. iii., pp. 542-4. 



9 Lot: eit., p. .=141. 



