MUSCLES OF TEE POSTEKIOR LIMBS. 



859 



Dog and Cat, the same muscle shows, in front, a eupernumerary fasciculus — a thick and long 

 strip mixed inwardly with the sartorius, and extending' vertically from the external angle of 

 the ilium to the patella, into whicli it is inserted by a short aponeurosis. 



The rectm femoris, in the Dog and Sheep, has only one branch of origin. 



The rectus parvus, that very tliin muscle, does not exist in Solipeds and Carnivora. 



2. Posterior Crural Region. 



A. Ruminants.— In the Ox, Shfep, and Goat, the biceps femoris is but little distinct 

 from the posterior portion of the superficial gluteus. It is longer and paler than in the Horse, 

 and its fibris are not penniform as in Solipeds. 



The semitendiiMsus has no sacral prolongation ; it arises only from the ischium. 



The semimemhranosiis is divided, in feriorly, into two branches: one, very thick, passes to 

 the f mnr; the other, much smaller, termi- 

 nates liy a tendon which is insinuated beneatli 

 the internal lateral ligament of the femoro- 

 tibial articulation, to gain the superior ex- 

 tremity of the tibia. 



In the Camel, an important peculiarity 

 should be noticed. In the | osterior crural 

 region is found an elastic apparatus n sem- 

 bling that in the anterior limb of this animal. 

 This is in the form of a thick fascia, which 

 descends from the supra-spiaous ligament and 

 the aponeurotic sheath of tiie coccygeal 

 muscles, is attached to the ischial tuberosity, 

 largely covers the space between the biceps 

 femoris and semitendinosus, crosses the sinus 

 of the femoro-tibial angle, and lies on the 

 retaining aponeurosis of the popliteus and 

 lateral txtensor of the phalanges. Here it 

 divides into two portions : the smaller is com- 

 posed of fasciculi a little apart, which pass 

 backwards and mix with similar fasciculi from 

 the inner surface of the thigh, and become 

 attached to the tendon of the gastrocnemius; 

 the larger portion descends in front of the 

 tarsus and metatarsus, and terminates towards 

 the lower third of that bone, on the surface 

 of the extensor tendons of the digits. The 

 use of this elastic layer is to flex all the articu- 

 lations of the abdominal limb in a passive 

 manner. 



The hicepi femoris in the Camel resembles that of the Horse. 



The semitendinosus is narrow in the middle, where it has an aponeurotic tint. 



Tlie semimembranosus is thicker tlinn the last-mentioned, but, like it, it is constricted in 

 the middle and expanded at its inferior extremity. It is attached, by its muscular fibres, to a 

 salient ridge above the internal condyle of the femur, and, by a short fibrous layer, to the 

 internal femoro-tibial ligament. 



B. Pig.— The biceps femoris of this animal is arranged like that of the Sheep. 



The semitendinosus and semimembranosus have a small point tliat ascends towards the root 

 of the tail, and represents the sacro-sciatic branch of the.«e two muscles in Sulipeds. 



C. Carnivora. — In these anitnals, the biceps femoris proceids from the ischium, and 

 divides, inferiorly, into two unequal branches: an anterior, the largest, terminates by an 

 aponeuro.sis which goes to the external patellar ligament and tibial crest; and a posterior, 

 attached to tlie tibial aponeurosis above and external to the gastrocnemius tendon. 



The semitendinosus and semimemhrauoKUK are as in the smaller Ruminants. 



SUPERFICIAL MUSCLES OF THE CROUP AXD 

 THIGH IN THE COW. 



, Midiile gluteal ; 2, 2, biceps femoris, anterioi 

 portion; 3, ditto, posterior portion; 4, semi- 

 tendinosus ; 5, tensor of the fascia lata. 



3. Internal Crural Region. 



A. Ruminants. — The sartorius in the Ox and SJieep is traversed, near its origin, by the 

 femoral artery. In the Camel, the gracilis is bifid ; the anterior branch is the smallest. The 

 pectineus of the Ox, single at its upper extremity, is divided into two branches at its inferioi 



