242 



ANATOMY OF VERTEBRATES 



interosseus cruris, fig;. 158, 120, extends obliquely between the 

 opposite margins of the leg-bones. The interossei digitorum 



158 



Muscles of hind-foot, Emys Europwa. xxxvm. 



dorsales, are shown at 122, and those of the plantar surface at 123, 

 fig. 158. 



The highest faculty of terrestrial locomotion in the reptilian 

 class, is manifested by the saltatory batrachians. 



In the hind limb of the frog there is a muscle which extends 

 from the diapophysis of the third vertebra to the ilium, which it 

 tends to protract, and acting from which it may slightly bend the 

 back. The ectogluteus receives an accessory strip from the 

 coccygeal style. The mesogluteus is a strong muscle. The ento- 

 gluteus and iliacus are united. The obturator externus has a semi- 

 circular form. The quadratus femoris is in two strata. There 

 are two pectinei and four adductores femoris. The extensor cruris 

 consists of a vastus internus and a vastus externus with a coalesced 

 crurceus ; there is no rectus femoris. The flexor cruris has but 

 one head or origin from the lower and back part of the ilium. 

 The semitendinosus has two heads, one from the fore part, the 

 other from the back part of the ischio-pubic symphysis. The 

 semimetnbranosus and gracilis have the usual attachments. The 

 sartorius resembles the rectus in its position and course in front of 

 the thigh: it is united to the tensor fascia lata. The gastro- 

 cnemius is represented by its external moiety, which is so large as 

 to give the appearance of a 'calf to the leg: its tendon glides 

 behind the tibio-tarsal joint, and expands as it descends along 

 the tarsal segment into a plantar fascia. The tibialis anticus 

 arises by a strong tendon from the femur, and divides at the 

 middle of the tibia into a fascicle inserted into the astragalus, and 

 a second inserted into the calcaneum ; in both at the proximal 

 end. A cruro-tibialis rises from the lower end of the femur, and 



