190 Mi?. F. E. BEDDARD ON THE [Feb. 19, 



four branches siij)plying the first four ribs. Their point of 

 opening is about opposite the second rib. 



In a young example of the African Red River-Hog {Potamo- 

 chcerus africanus) the azygos was also limited to the left side of 

 the body, as in Porcula scdvania. In Potamochijerus, however, 

 this vein enters the heart as in Ungulates ; while in Porcula it 

 seems to have the relations of the azygos in Marsupials &c., where 

 a left azygos is present. The difference is not really of great 

 imj)ortance as indicative of an anomaly in one or the other of these 

 two genera of Suida3 ; for we have in other Ungulates — e.g.,\n 

 Connochates grnt — a left azygos which is divided into two parts 

 whereof one opens into the jugular and the other into the heart. 

 One or other arrangement is found in each of the Suine genera 

 Porcula and Potamochcerus. Potamochcerus shows the arrange- 

 ment which was found in Sus scrofa by Hunter * and quoted by 

 Owen in his ' Comparative Anatomy ' t in dealing with the 

 azygos veins of mammals. 



In the Pygmy Hog {Porcula salvania) the azygos vein is only 

 developed upon the left side of the body ; there was absolutely no 

 trace of this vein that I could discover upon the right side. It is 

 large and thick, and its branches are imjDortaiit and obvious with 

 the exception of the first. This more slender branch divides on 

 issidng from the main trunk into three twigs, of which two run 

 on each side of a rib. After this there aTe seven branches, which 

 are large and were turgid with blood in the individual examined. 

 These branches coi-respond of course regularly to the ribs ; but 

 they supply eight intercostal spaces, since the last of them, in 

 which the azygos ends, bifurcates over its rib. The azygos lies 

 very definitely upon the left side of the aoita ; it is not median in 

 position as is so often the case with this vein. The vein ended 

 in front of the diaphragm ; nor could I detect any branch, however 

 thin, which continued on the main trunk behind the diaphragm in 

 the direction of lumbar veins or of the postcaval or renal veins. 

 These observations refer to one example only, which was a female. 



The Musk Deer [Moschiis moschiferus) j^resents us with a system 

 of azygos veins like those of other Ungulates. On the left side 

 the well-developed azygos enters the auricle directly. On the right 

 side the small azygos consists of one vein only. In front of this, 

 and on both sides of the body, is a superior intercostal. 



Dorcatherium aquaticum did not show, as might perhaps have 

 been expected, an arrangement of a specially primitive character. 

 It is much like other Ungulates. There is a small azygos 

 on the right side of the body formed by three affluents only. 

 The azygos of the left side only communicates with the right 

 auricle. It is as extensive as is usual among Ungulates and con- 

 sists of many intercostal affluents. The first of these branches is 

 made up of two tributaries. There is no anteriorly running 



* 'Essaj's and Observations on Natural Historv &c,,' arranged b3' Richard Owen, 

 vol. ii. 1861, p. 124. 

 t Vol. iii. 1868, p. 555. 



