226 MR. F. E. BEDDARD ON THE [Feb. 1, 



ventricular valve and connect the successive papillary muscles. 

 The arrangement of these is such as to suggest a former great 

 extension of the membranous valve towards the apex of the 

 ventricles. 



It seems to me from the account given by Gratiolet * of this 

 valve, that in the specimen which he dissected the papillary 

 muscles of the septal half of the valve were not much developed. 

 Otherwise there is no great difference between his account and 

 that given above, save that I have entered into the matter some- 

 what more in detail. 



Dr. Crisp, in his account of the Hippopotamus, remarks of the 

 right auriculo-ventricular valve that the " tendons of the Tricuspid 

 valve, seventeen in number, spring from three columns (so-called), 

 one prominent and nipple-like, the others but little raised above 

 the surface." I fancy from this account that the specimen 

 examined by that anatomist was not unlike the one described by 

 myself in the present communication. My figure shows a number 

 of chorda? tendinese which is not very far from the number 

 asserted by Dr. Crisp, while his description of the musculi papil- 

 lares, although not absolutely agreeing with the arrangement of 

 those muscles as I saw it, emphasizes, as I think, the stout 

 elevated muscle to the extreme right of the ventricular cavity in 

 the figiu-e. 



The accompanying figure (text-fig. 24) represents the interior 

 of the right auricle of the Hippopotamus, which has never been 

 figured so far as I am aware, though many of the features 

 there visible are referred to by previous writers. The auricular 

 appendix, shown to the right of the drawing, is not completely 

 opened up. A seeker is shown passing through the auriculo- 

 ventricular orifice and appearing below, the ventricle being 

 supposed to be completely removed. This will serve to orient 

 the various parts of the auricle. Those parts of the auricle where 

 the endocardium is very thin so as to expose the musculature, are 

 represented as striated to emphasize this muscular appearance. On 

 the right upper side of the drawing is seen the precaval vein (A.C.), 

 which debouches very close to the orifice of the azygos (Az.). 

 The arrangement is, in fact, exactly that of the Peccary (Dicotyles 

 torquatus), of which animal I dissected a heart for the purposes 

 of comparison with that of Hippopotamus. The circumference 

 of the mouth of the azygos is 46 mm., while that of the precaval 

 I calculate to be fully 60 mm. It is obvious, however, that the 

 azygos is relatively very large. It has been already observed 

 that the postcaval vein is very small where it debouches into the 

 auricle. This is certainly the case in the heart which I examined 

 and as is shown in the drawing (text-fig. 24, P.C.). 1 find on 

 reference to the heart of the Peccary, that the conditions ob- 

 servable in the Hippopotamus are only an exaggeration of what 

 is to be seen in the former animal. In the Peccary the postcaval is 



* Loc. cit. p. 358. 



