462 COMPARATIVE ANGIOLOGY. 



arch underneath the flexor tendons ; from this arch are given off three digital 

 or plantar arteries, which are distributed like those of the superficial palmar 

 arch in the anterior limb. 



The brachial arteries in the main resemble those of the hog. The vertebral 

 inosculates with the ranius anastomoticus ; it supplies many cervical branches, 

 the superior cervical artery being both small and short. The humeral artery 

 gives off branches resembling those described in the typical animal, but it 

 terminates by dividing into radial and cubital arteries, the presence of the 

 anterior radial being merely indicated. The cubital artery gives off the inter- 

 osseous, which divides under the pronator quadratus, into anterior and posterior 

 branches ; the former passes between the radius and the ulna, forms a carpal 

 plexus, and supplies the digits anteriorly ; the latter is the larger, and in the 

 region of the carpus divides into a superficial and a deep branch ; the first 

 assists with the cubital in forming the superficial palmar arch, which is chiefly 

 formed by the inosculation of the cubital and radio-palmar arteries ; the deep 

 branch helps with the radial to form the deep palmar arch, underneath the 

 flexor tendons. From the latter arch are given off eight interosseous branches, 

 four palmares and four dorsales, the latter passing through the intermetacarpal 

 spaces and anastomosing with branches of the anterior interosseous artery. 

 All these vessels pass down the digits, and join ultimately the collateral 

 palmars, which emanate from the superficial palmar arch. Thus there are 

 three sets of digital vessels, an anterior, and a superficial and deep posterior. 



The carotid arteries arise singly from the brachio-cephalic trunk, but other- 

 wise resemble those of the horse ; in their breaking up and in the disposition 

 of the occipital artery and ramus anastomoticus there is no important devia- 

 tion. The internal carotid enters the carotid canal, passes forwards, and sends a 

 projecting loop out through the carotid foramen, receiving a small branch of 

 the external carotid ; it joins the spheno-spinal and recurrent ophthalmic 

 branches, forming a kind of rudimentary rete mirabile. 



The glosso-facial artery is represented by separate facial and lingual 

 branches. 



The internal maxillary artery resembles that of the horse ; the superior 

 dental is usually regarded as its continuation. It gives off an alveolar artery 

 which chiefly supplies the orbital gland. 



The receptaculum chyli in carnivora is very large, extending forwards as far 

 as the thorax. The thoracic duct usually bears a marked resemblance to that 

 of the hog. 



KODENTIA. 



Even were the subject of importance, there is little space for its consideration 

 here. It is, however, interesting to note that the heart presents external indica- 

 tions of division, the apex being in some cases slightly cleft. The external 

 jugular vein is very much larger than the internal, and there are two separate 

 anterior venae cavse. 



AVES. 



The heart in birds is divided into four cavities as in mammals ; its apex is 

 situated between the lobes of the liver, as there is no absolute separation be- 

 tween the thoracic and abdominal cavities. 



