402 COMPARATIVE AXGIOLOGY. 



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

 or plantar arteries, \vhich 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 Avith the ramus anastomoticus ; it supplies many cervical branches, 

 the superior cervical artery being both small alid 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 2}almar arch, which is chieflj^ 

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

 branch helps with the radial to form the deej) jjaZma?- arch, underneath the 

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

 four imhnarcs 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 dee]) 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 (jlosso -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 oft' an alveolar artery 

 which chiefly supplies the orbital gland. 



The receptacxdum 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 rftvmW, the apex being in some cases slightly cleft. The external 

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

 anterior vena3 cavaj. 



AVES. 



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

 i^ituated between the lobes of the liver, as there is no absolute separation be- 

 iween the thoracic and abdominal cavities. 



