556 THE AMTEBIE8. 



From this anastomosis results, as in the Horse, two series of metatarsal branches-^ 



profound and a superficial. _ , „ ,, j. • j. i. j., 



Tlie profound branches, two or three m number, form on the posterior taoe ot the 



metatarsal bone, below the suspensory ligament, the posterior interossea;, mixed witli 



two or three reticulated venous branches, and anastomose by their inferior extremity 



with a perforating branch of the collateral of the cannon. 



The superficial branches, similar to those which accompany the plantar nerves in the 



Hiirse, are of very unequal calibre : tlie external is so rudimentary that it often escapes 



dissection ; the internal in reality continues the plantar artery of the same side. Both are 



united to the perforating branch already noticed. 



Anterior tibial artery. — After passing down along the leg on its antero-external face, 



as in Solipeds, tliis vessel arrives on the hock, where it takes the name of pedal 



artery, and furnishes the perforating-pedal artery; it is continued by the metatarso pedal 



or collateral artery of the cannon. 



a. The perforating pedal artery does not differ from that of the Horse. 



b. The metatarso-pedal, or collateral of the cannon, descends, flanked by two satellite 

 veins, in the channel on the anterior face of the metatarsal bone, giving off towards the 

 inferior extremity of that channel the perforating^ branch already spoken of, and is 

 continued into the digital region as the common digital artery. 



The perforating branch of the collateral of the cannon passes into the foramen pierced 

 from before to behind, across the inferior extremity of the metatarsal bone, arriving 

 beneath the suspensory lig.iment, and tlien divides into seveial ascending and descending 

 branches. The first join the deep and superficial posteiior metatarsal arteries furnished 

 by the plantar and pedal perforating arteries. Among the second, we notice three digital 

 ai'teries, facsimiles in miniature of those which will be described in the anterior 

 limb : two lateral, descending on the excentric side of the phalanges ; a median, 

 turning within the flexor tendons to place itself behind them on the middle line of the 

 digital region, and prolonged into the interdigital space, where it anastomoses with a 

 branch of the principal artery of the digits. 



The latter artery, the common digital, descends into the space between the digits, 

 after passing beneath the capsular ligament of the metatarso-phalangeal articulations, in 

 tlie notch comprised between the two articular surfaces of the metatarsal bone, and 

 terminates above the inferior extremity of the first phalanx by two ungueal arteries, 

 ' whose description will be reserved until describing the arteries of the anterior limb. 

 In the number of collateral branches emanating from this vessel, there may be particularly 

 remarked a large off-shoot which arises a little before the separation of the two ungueal 

 arteries, and is directed from before to behind, dividing at the posterior part of the 

 interdigital space into several divisions, the principal of which are : 1, Two transverse 

 branches passing between the flexor tendons and the phalanges, to be joined to the 

 lateral digital arteries ; 2, A single ascending branch, joining with the posterior median 

 digital artery; 3, A descending branch, also single, dividing into two portions which 

 reach the heels, to be distributed to the plantar cushion and tlie villous tissue. These 

 branches represent the arteries of the plantar cushion in the Horse, and will be noticed 

 more in detail in the description of the arteries of the anterior limb, where in 

 principle they are found to be exactly like these. 



2. External Iliac Arteries of the Pig. 

 The distribution of these vessels in the Pig is remarkably like that we have described 

 as existing in Ruminants, even in the terminal portions of the limbs, notwithstanding 

 the complete development of the two lateral digits. It may be noted, however, that the 

 posterior tibial artery is somewhat slender, and that it is singularly reinforced by its 

 anastomosis with the saphena artery, whose dimensions are relatively considerable.' 



3. External Iliac Arteries of Carnivora. 



The crural trunk is divided in the Carnivora, as in the other animals, into three 

 sections: the proper iliac artery, the femoral artery, and the popliteal artery, terminated 

 by the tibial branches. 



Proper iliac arien/.— This vessel does not give rise to any branch, as the cir- 

 cumflexa ilii comes directly from the abdominal aorta. 



' In small Euminants, the posterior tibial artery, properly speaking, is equally 

 rudimentary; the saphena artery constitutes the principal vessel. From °a note which 

 we made a long time ago, it appears the first vessel is altogether absent sometimes, and 

 that the p'antar divisions come exclusively from the saphena, as in the Carnivora. 



