84 THE SALAMANDER 



appear that again this muscle is to be regarded as a case of the inci- 

 pient separation of two muscles primitively united. The 'abductor' 

 portion probably assists in supination (cf. Ribbing). 



MM. extensores breves digitorum (m.e.b.). Ribbing (1907). 



Extensor brevis Cams (1828). 



Extensores et adductores .... Stannius (1854-6). 



Extensor digitorum brevis s. profundus . . Humphry (1872). 



Carpo-phalangei ...... Hoffmann (1873-8). 



Extensor brevis superficialis digitorum +Extensor brevis profundus 

 digitorum ........ Eisler (1895). 



Courts extenseurs des doigts (72-7) .... Perrin (1899). 



Extensores digitorum breves s. profundus III-IV . Osawa (1902). 



Extensores digitorum II, III, et IV. . . Sieglbaur (1904). 



These small muscles arise in two layers. The more superficial and 

 thicker stratum takes its origin from the ulnareAr intermedium and the 

 OS centrale (for the second digit), while the deeper and thinner layer 

 arises from the basal carpalia, each muscle springing from the basal 

 of the corresponding digit. The two strata of the muscle are separated 

 by the branches of the A. perforans carpi. They have a tendency to 

 unite distally into long thin tendons which pass along the extensor 

 surfaces of the fingers and are inserted on the proximal end of each 

 phalanx. 



Innervation: From the NN. dorsales manus inter, and ulnaris. 

 Function : Extensors of the fingers. 



M. extensor lateralis digiti quarti (m.e.l.d.4.) (mihi). 



Court deducteur du quatrieme metacarpien (80) . Perrin (1899) 



First described by Perrin, this very small muscle arises from the distal 

 external angle of the ulnare + intermedium and is inserted laterally 

 on the proximal angle of the fourth metacarpal. Its fibres are accord- 

 ingly very short. 



Innervation : From N. dorsalis manus ulnaris. 



Function-. To assist in extending the hand by drawing the fourth 

 digit laterally. Opposer of the MM. intermetacarpals. 



5. Flexor muscles of the Fore-arm and Hand (PI. VII, figs. 45 



and 46). 



These should be dissected from the ventral side. They are more 

 numerous than the extensor muscles. 



M. flexor primordialis communis (m.f.p.). Ribbing (1807). 



Flexor digitorum (29) ...... Carus (1828). 



Palmaris superficialis . , Eisler (1895); McMurrich (1903). 



