1893.] TEETEBEAL A>'D LIMB-SKELETOX OE THE AMPHIBIA. 277 



it was only possible for this to act as a support under undue 

 extension of the two remaining digits. 



On laying bare the enclosed skeleton, it was observed that mus- 

 cular elements were largely wanting in relatioii to this presumed 

 inner digit, and that that really represented the first and second 

 digits, bound up in a kind of syndactyly. The second one 

 (II, fig. 16) was abnormally bent upon itself in an inward direction, 

 and its terminal phalanx was firmly united to the single one of the 

 first digit by a powerful ligament (l(j) which rendered independent 

 movement of the parts impossible. 



On turning to the rest of the limb-skeleton, the tibia and fibula 



^^y. 



Hind limbs of Salamandra inaetdosa, adult $ . 



Fig. 15. Skeleton of left hind limb, ventral aspect. Fig. 16. The same, right 

 hind limb, dorsal aspect, for comparison with its fellow. The contour- 

 lines of the undissected limbs are indicated, and the darker areas delineate 

 centres and degrees of ossification. 3 times nat. size. 



c, cenlrale ; /, fibula ; ,/Z/, fibulare ; /, intermedium; Ig, ligamentous 

 fibres ; t, tibia ; th, tibiale ; ts i-v, tarsaUa ; I-V, digits. 



(<,/) and the metatarsals and phalanges of the three innermost 

 digits were all normal in their relative sizes and degrees of ossifi- 

 cation. The fourth digit, however, although possessed of its full 

 complement of phalanges, instead of being the longest of the series, 

 as is most generally the case in this species, had undergone an 

 arrest of growth, whereby it remained much shorter than the 

 third. The latter digit had, in fact, usurped its function ; and com- 

 parison of the figures will show that the proportionate relation- 

 ships between the 3rd and 4th digits of the I'educcd limb (fig. 16) 

 were approximately those of the 4th and 5th of the normal one 

 (fig. 15). There was no trace either of a fifth digit or of its related 

 tarsale. The tarsal elements of the reduced limb, while fully 

 representf.'d for the digits ju'csent, were remarkable for the complete 

 co-ossification of the 3rd and 4th tarsalia {ts iii, iv, fig. 10). On 

 further comparison with the normal tarsus, it was seen that all 



