The appendicnlar muscles of Necturus maculosus. 417 



adjacent to it on the distal side, furnish the points of origin for 

 the two sets of Short flexors of the digits. Proximal to this parti- 

 tion the plantaris profundus becomes inserted into the dorsal (inner) 

 surface of the fascia. The entire set of muscles thus united into 

 a System through the medium of the plantar fascia includes both 

 superficial and deep plantar muscles. as well as the two sets of 

 short flexors, superficiales and profundi, and the whole System acts 

 as a Compound flexor of the digits. 



As in the case of the corresponding fascia of the forearm and its 

 similarly related muscles, there has been a general tendency to consider 

 the System the equivalent of a long flexor, and the muscles have been 

 frequently so named. The nomenclature adopted here is that of HcMüKKICH, 

 1903, in the forepaw of Amblystoma, the observations being made by 

 means of serial sections. An equally recent author, OsAWA, who has 

 described the condition in Oryptobranehus, refers to the entire system as 

 M. flexor digitorum (longus) sublimis, the appellation "longus" being used 

 only in the case of the forearm. 1t is likely that this difference in the 

 use of names does not rest upon any marked differences in the species 

 studied, but is due rather to the individual point of view, and emphasizes 

 the fact that we have in the Urodeles the volar muscles at an interesting 

 point in their differentiation from an indifferent volar mass to that of the 

 long flexors characteristic of higher forms. 



M. plantaris superficialis (ps). This is a short, broad 

 muscle, occupying the proximal half of the lower leg, and continued 

 directly into the plantar fascia. It arises by fleshy fibers from the 

 middle of the inner surface of the distal epiphysis of the femur, 

 above (proximal to) the origin of M. flexor tibialis. From their 

 origin the fibers diverge and form a broad belly, which inserts, when 

 at its greatest breadth, into the proximal margin of the plantar 

 fascia. 



See notes to palmar and plantar fasciae, and to H. palmaris super- 

 ficialis. 



M. plantaris profundus (pp). This is a large muscle-mass, 

 which lies beneath the plantar fascia, and corresponds closely to 

 its homolog in the band. Like this it is divided into two masses by 

 a lougitudinal bündle, the fibulari-tarsalis, exactly as the palmaris 

 profundus of the hand is divided by the ulnari-carpalis, but there 

 are several minor points of difference in the area of origin. In both 

 cases it is in the form of a line or narrow band, and here, as in 

 the hand, this line runs down the shaft of the inner long bone and 

 its corresponding tarsal (tibia and tibiale) but in the leg it does 

 not become recurved and again cross the tibia, but runs over the 



Zool. Jahrb., Suppl. XV (Festschrift für J. W. Spengel Bd. II). 27 



