68 STUDIES IN COMPAKATIVE ANATOMY. 



HEAKT AND VESSELS.^ 

 Heart. 



The heart of the elephant has been repeatedly dissected, and 

 may now be treated briefly. For fuller particulars the reader 

 may consult Vulpian and Philipeaux,^ together with the correc- 

 tions and additions of Dr Morrison Watson. 



The pericardium is pointed forwards, where it is united to the 

 base of the heart. Two fibrous cords pass from the back of the 

 pericardium to the tendinous centre of the diaphragm. Dr 

 Watson finds them specially connected with the anterior of two 

 plates of yellow elastic tissue which cover the two surfaces of 

 the muscular portion of the diaphragm. He observes further 

 " that the pericardiac band of the right side was entirely com- 

 posed of that peculiar form of yellow elastic tissue which, so far 

 as I am aware, has only once before been described, and that in 

 the ligamentum nuchse of the giraffe by Mr Quekett. In the 

 left band, as well as in the plate into which the bands expanded, 

 the elastic tissue presented the usual appearance." Vulpian and 

 Philipeaux speak of the fibrous band as single. 



The base of the heart is depressed forward, and the interven- 

 tricular septum is nearly vertical and longitudinal. In the fol- 

 lowing remarks we shall use terms of direction and position with 

 reference to the natural state of the parts. The base is under- 

 stood to be anterior, the apex posterior, and the right auricle 

 dorsal or superior. 



With respect to the general form of the heart, the separation 

 of the apices of the ventricles is the most important feature.^ 

 Vulpian and Philipeaux say : " II n'y a pas de sillon inferieur 

 inter-ventriculaire nettement dessine. II y a, au contraire, un 

 sillon superieur tres profond, qui, du milieu de la base du coeur, 

 se porte au voisinage de la pointe." In our example the case was 



^ It was our first intention (supra, p. 8) to omit the heart, lungs, and liver, 

 seeing that Messrs Vulpian and Philipeaux have described them so minutely, but 

 on comparing their account with our dissection, and with Dr Watson's notes, 

 we find not a few discrepancies of greater or less importance. A short notice of 

 these viscera is therefore included in the present memoir. 



2 Ann. Sci. Nat. Zool. 4^ ser. tom. v. p. 183 (1856). 



3 In some Cetacea the apex of the heart is indented, while in Sirenia, parti- 

 cularly in the dugong, the separation of the ventricles is even more marked than 

 in the elephant. 



