HEART OF CARNIVORA. 523 



either the postcaval or coronary veins : the contrast presented 

 by the Elephant, in this respect, is significant. The strong 

 chordae tendineaa of the tricuspid connect it, in most Ungulates, 

 with three obtuse and transversely oblong earn e as columnar : one 

 rising from the movable wall, a second from the septum, and a 

 third smaller one from the anterior interspace between the fixed 

 and movable walls : the tendons diverge from each column to 

 the two contiguous moieties of the divisions of the tricuspid a 

 provision ensuring the simultaneous action and outstretching of 

 the three portions of the valve. Two smaller columns placed 

 opposite to each other, one on the free, the other on the fixed 

 wall, are connected in the Rhinoceros and manv other Ungulates, 



> O 



by a single strong tendon passing across the cavity from the apex 

 of one to the other. 1 In the Hog some of the tricuspid tendons 

 pass to a thick short e column ' projecting from the free wall, 

 others pass directly into the smooth convex fixed wall of the 

 ventricle. 



In most Ruminants, especially the larger kinds, there is a bent 

 bone at the base of the heart, on the septal side of the origin of 

 the aorta, and imbedded in the tendinous circle which gives 

 attachment to muscular fibres of the ventricle ; in the Giraffe 

 this bone was two-thirds of an inch in length. Two such ossifi- 

 cations of the sclerous tissue have here been met with in Oxen and 

 Red-deer: an ossified and an unossified piece of fibro-cartilage 

 are more commonly observed : in the Horse these bodies at the 

 septal side of the aortic ring are rarely ossified until extreme 



age. 



F. Heart of Carnivora.- -In the present group the heart is more 

 obtuse at the apex, and the left ventricle forms a greater share 

 thereof, than in Ungulates. The Eustachian valve is wanting in 

 most Carnivora; Avhere indicated, its remains have been found in 

 the smaller kinds, as the Weasel, Polecat, Ichneumon, which by 

 their size resemble the immature of the larger species. The 

 inner surface of the ventricles, especially the right, is more fasci- 

 culated, and the number of carneaa columnar is greater than in 

 Ruminants. A condensation of the sclerous tissue of the aortic 

 ring in the Lion and Tiger, at two points, indicates the homologues 

 'of the heart-bones in Ungulates. In these and other Felines the 

 mammillary columns are continued from the septal end of a strong 

 trabecular tract between the { fixed ' and f free ' walls of the right 



o 



ventricle. The heart in Phocidce is broad and somewhat flattened, 



1 I have not found, in Ruminants, so exclusive an origin of the mammillary columns 

 from the ' free' or external -wall, as described in ccxxxix. t. in. p. 502, after CLXXXV". 



