THE MUSCLES 105 



ventralismaybe attributed. In them again, there is a rectus internus(Humphry). 

 There is no reason to beheve that either this or the pubotibiahs (with metazonal 

 innervation) were ever present in pro-ReptiHa. A study of modern Urodela, 

 moreover, points to a progressive differentiation of M. pubotibiaHs, with the 

 formation of an "adducteur du femur" (Perrin) perhaps better distinguished as 

 a distinctive urodele formation by the term M. pubtfemoralis. . . . The 

 femoro-fibular muscle (Humphry) of urodeles appears to be a caenotelic 

 structure, being apparently unrepresented in Salientia and Amniota. There 

 is, again, no definite evidence that the fore-runners of Amniota ever possessed 

 the caudocrural muscle (of Humphry), which has probably been derived in 

 urodela from a common caudofemoral mass along with the caudalifemoralis 

 (of de Man). 



'The attachments of the caudo-crural and the course of the N. perinealis 

 favour this interpretation rather than a derivation of the caudocrural from the 

 ischiocaudal.' 



M. pubo-ischio-femoralis internus (m.p.i.f.i.).^ de Man (1873); Siegl- 

 baur (1904); Low (1926). 



Crassis femoris tensor s. protractor (31) . . . Carus (1828). 



Pectineus . Meckel (1828); Stannius (1854-6); Appleton (1928). 



Intra-pelvi-femoral Duges (1834). 



Iliacus Mivart (1869). 



Anterior-suprapubic-portion of the deeper stratum of the plantar of thigh 



s. pectineus Humphry (1872). 



Pubo-ischio-femoralis internus (Adductor) . Hoffmann (1873-8). 



Extenseur du femur (121)2 Perrin (1892). 



Together with M. extensor iliotibialis = 



Extensor femoris biceps (Caput pubicum) . . Osawa (1902). 



A very large, powerful muscle arising from the whole internal face of 

 the pubis, and from part of that of the ischium and ilium. It bends 

 around the anterior edge of the pubis, and passes down the anterior 

 aspect of the thigh. It is inserted along the whole anterior face of 

 the femur with the exception of the extreme ends. As disclosed by 

 its innervation it belongs to the dorsal, or extensor muscles. 



Innervation-. From N. femoralis, and a few twigs proximally 

 from N. obturatorius. 



Function : It has only a relatively slight influence in extending the 

 limb in a dorso-ventral plane, but has a very pronounced action in 

 drawing the femur towards the body anteriorly. 



Criticism of Perrin. 



Hoffmann describes a muscle under the name 'Pubo-ischio- 

 femoralis internus' which he says Von der oberen (Bauch-) Flache 



J See also M. pubo-extensorius, p. 106. ^ See 'Criticism of Perrin'. 



