472 THE ANATOMY OF VEETEBRATED ANIMALS. 



genus, Inuus, proper caudal muscles are present. In the limbs 

 there is a levator claviculcB which passes from the transverse 

 process of the atlas to the acromion ; a dorso-epitrochlearis, 

 consisting of a muscular bundle detached from the latissimus 

 dorsi near its insertion, and passing to the distal and inner 

 end of the humerus, or even further down ; a scansorius, from 

 the ventral edge of the ilium to the great trochanter, which 

 sometimes becomes confounded with the glutceus minimus ; a 

 special abductor ossis metacarpi quinti ; and a peroruBUs quinti 

 digiti, arising from the fibula, between the peronceus longus 

 and brevis, passing behind the external malleolus, and send- 

 ing its tendon to the extensor sheath of the fifth digit. 



The extensor priyni internodii pollicis and the peron(Bii,s 

 tertius are absent in this, as in the preceding gi'oup. 



The biceps femoris usually possesses only an ischial head, 

 and the soleus arises only from the fibula. The flexor brevis 

 digitorum arises partly from the tendon of the plantaris, 

 where this passes over the pulley on the postex-ior surface 

 of the calcaneal process to become continuous with the 

 plantar fascia, and partly from the tendons of the long 

 flexor. The transversus pedis is usually fidly developed, 

 but has only two heads of origin from the distal ends 

 of the second and third metatarsals. The ifiterossei pedis 

 are just visible on the dorsal aspect of the foot, but none 

 are, properly speaking, dorsal. None of them are penni- 

 form muscles arising from adjacent sides of the metatarsal 

 bones ; but they are attached, in pairs, to the plantar and 

 lateral aspects of the metatarsal bones of the digits to which 

 they appertain. They are inserted into the sesamoid bones, 

 of which each digit has two, and into the bases of the proxi- 

 mal phalanges, and give off no distinct tendons to the 

 extensor sheaths. Additional muscles may arise over the 

 proximal ends of the metatarsal bones, and pass to the 

 three fibular digits. 



The interossei mands are very similar to those of Man, 

 being divided into a dorsal and a palmar set, and sending 

 slips to the extensor sheaths of the digits, without that 

 complete subdivision which is seen in the Antliropomorpha. 



