378 THE ANATOMY OF VERTEBKATED ANIMALS. 



lares, arise from the middle caudal vertebras, and, after re- 

 ceiving fibres from, the ventral region, end in the dorsal mar- 

 gins of the orbicularis. 6. Two muscles attached to the 

 pinn£e of the ears {auriculo-orhiculares) pass backward to the 

 orhicularis on each side. 



On the ventral aspect are certain muscles which assist the 

 orhicularis : 1. Two broad muscles {sterno-faciales) arise in 

 the middle line, over the anterior part of the sternum, and 

 pass outward and forward to the sides of the lower jaw and 

 the integument of the face and ears. Muscular slips from 

 these are sent up over each shoulder to the orhicularis. 2. A 

 hwnero-ahcloininalis arises from each humerus beneath the in- 

 sertion of the 2^^cloralis major, and, passing backward over 

 the sides of the abdomen, these become connected with the 

 ventral edges of the 07'hicularis. The external fibres of these 

 muscles are continued round the ischial regions to the coccy- 

 geo-orhicularis j the internal fibres pass to the prepuce, and 

 over the middle line of the abdomen, in front of it. 3. A Jiur 

 mero-dorsalis arises from the humerus close to the foregoing, 

 and, passing upward and backward through the axilla, spreads 

 out in the mid-dorsal integument and the orhicularis. 



The contraction of all these muscles must tend to bring 

 togther the edges of the integumentary bag, and to tuck the 

 head, tail, and limbs into it. 



In the myology of the limbs the following points are note- 

 worthy : The supinator longus, pronator teres, and palmaris 

 longus, are absent. The p>almaris hrevis is present. A single 

 muscle takes the place of \\\e extensor secundi interyiodii p)olli- 

 cis and extensor indicis, and sends a third tendon to the mid- 

 dle digit. The extensor ininiwd digiti supplies the other two 

 digits. The flexor perforans and flexor pollicis longus are rep- 

 resented by five distinct muscular heads, each with a tendon 

 of its own ; but all the tendons unite in the middle of the fore- 

 arm, and the common tendon again subdivides into only four 

 slips, the poUex receiving no tendon. There are no lurnhrica- 

 les. The pollex has only a rudimentary j^Cicor hrevis and an 

 abductor. The other digits have each two interossei, ov flex- 

 ores breves, inserted into the metacarpo-phalangeal sesamoids. 



In the leg, the soleus has only a fibular head, and ihe flexor 

 hi^evis digitorum arises wholly from the calcaneum. ^he flexor 

 hallucis and flexor perforans have a common tendon, which, 

 in the sole, divides into five tendons, one for each digit. 

 There are no lumhricales, nor flexor accessorius. The tibialis 

 posticus seems to be represented by twc small muscular bel- 



