228 MR. F..E. BEDDAKD UN THE [Feb. 1, 



of less diameter than the azygos where both enter the heart. The 

 letters b.v. in the text-figure indicate a depression in the wall of 

 the auricle, which is here thick and muscular, as is also shown in 

 the figure. Beyond this (i. e., in the direction of the auriculc- 

 ventricular valve) the wall becomes thin and white and very 

 tough, suggesting the wails of a vein. This, however, can hardly 

 belong really to the cut vena cava, the position of which would 

 in that case become totally different to that of the Peccary. 

 Beyond this point the walls of the auricle again become muscular, 

 and a very sharp semicircular fold, as shown in the text-figure, 

 marks the commencement of this muscular region. The fold is 

 a little beyond (i. e., towards the appendix auriculae side) the 

 entrance of the coronary vein. In the Peccary's heart the wall 

 of the auricle is muscular for a much greater distance towards 

 the orifice of the postcaval, and there is no membranous region, 

 such as I have described above, opposite to the orifice of the 

 coronary vein ; indeed the muscular layer is seen to extend over 

 about one-half of the flap which guards the orifice of the coronary 

 vein. Nevertheless, beyond this point in the direction of the 

 entrance of the postcaval the auricular wall is thin and mem- 

 branous, i. e., non-muscular. This fact gives me confidence in 

 restricting the postcaval embouchure to the area lettered P.C. in 

 the accompanying figure. It is therefore evidently a very small 

 orifice relatively speaking. It may be seen also in the figure 

 referred to (text-fig. 24, B) that the postcaval opens into an 

 almost separate chamber of the auricle which is separated from 

 the auricle itself by a high and broad ridge, beneath which, on 

 the opposite side, lies the orifice of the coronary vein. Other 

 than this there is no structure which can be termed an Eustachian 

 valve. It will be seen in the figure that besides the pit in the 

 auricular wall lettered b.v., there are a few other and similar 

 orifices scattered over the inside of the right auricle. These, 

 which are not numerous, are to be regarded, I imagine, as the 

 equivalents of the foramina Thebesii of human anatomists. I 

 did not find the second precaval vein which Macalister has stated 

 to be present in the dwarf Liberian Hippopotamus. 



Through the kindness of Mr. B. H. Burne, I have been able to 

 examine the heart of a Hippopotamus preserved in the Miiseum 

 of the Royal College of Surgeons. The heart was a small one 

 and obviously that of a foetal or new-born animal, for the com- 

 munication between the auricles was present, and the ductus 

 Botalli was a wide vessel connecting the aorta and the pulmonary 

 artery. I looked particularly at the relative sizes of the postcaval 

 and precaval veins at their embouchure into the auricle ; and 

 although I am not able to give actual measurements, it was 

 perfectly clear that both veins were roughly of the same size ; in 

 any case it is absolutely safe to say of this particular heart that 

 the postcaval was not markedly smaller than the precaval. 

 Gratiolet is very positive about the fact that in a young Hippo- 

 potamus which died about 24 hours after its birth, the postcaval 



