98 THE SALAMANDER 



continuous from the head to the tip of the tail, although the sub- 

 vertebral portion is somewhat deficient in the sacral region. The 

 anterior fibres are inserted on the postero-ventral aspect of the 

 occipital region of the skull. 



Innervation: From the ventral rami of the spinal nerves. 



Function-. The -pars suhvertehralis flexes the spine. The pars 

 transversalis also tends to flex the spine if both sides contract simul- 

 taneously, but if they contract alternately then a lateral flexion of the 

 spine would occur. The function of the pars obliqua interna is 

 similar to that of the obliqua externa (q.v.). 



4. Caudal Muscles. 



The caudal muscle mass is dorsally very similar to that of the body. 

 The anterior part forms the M. ilio-caudalis (m.il.cd.), the fibres of 

 which arise from the first two or three caudal vertebrae and are 

 inserted on the ilium. The dorsal and ventral muscles of the tail are 

 continuous laterally, forming strong C-shaped masses of muscle on 

 either side of the vertebrae. In the mid-ventral line the muscles of 

 the two sides are separated by a tough ligament which attaches the 

 spines of the haemapophyses to the skin, while dorsally there is a 

 deep median groove between the muscles wherein lie the cutaneous 

 glands. 



The ventral muscle of the tail shows some slight tendency to 

 differentiation in so far as some of the fibres pass from one haemapo- 

 physis to the next instead of lying between myosepta, but the dis- 

 tinction is not clear enough to justify their separation as an individual 

 muscle. 



Innervation: From both dorsal and ventral rami of the spinal 

 nerves. 



Function: They obviously serve as the motors of the tail. 



MUSCLES OF THE HIND-LIMB AND PELVIS 

 (Pis. VIII and XVI) 



I. Historical. 



In general the hind-limb does not seem to have received so much 

 attention as the fore-limb. One of the earliest workers to make a 

 special study of its muscles is Perrin (1892). His work is very care- 

 ful and detailed, but, as has already been noted in discussing his 

 work on the arm muscles, it suffers from the absence of correlation 

 with the nerves. Eisler's work (1895), already mentioned, covers 



