1888.] 



THE CARPUS AND TARSUS Of THE ANURA. 



151 



Unterlage fiir den Fersenhocker, der vielfach als Grab-Instrument 

 benutzt wird, zii gewinnen." 



We have already called attention (p. 150) to the development of 

 a retral process from that which we regard as the hallux -meta- 

 tarsal. In Ttyla lichenata this is completely segmented off (* in 

 •woodcut, fig. A), forming one of a series of marginal elements, 



Fig. A. 



The pre-hallux of opposite sides in Hyla lichenata. Dorsal aspect. 



X 6. 



which skirt the outer face of the calrar and are, moreorer, 

 roughly symmetrical on opposite sides. Comparison of this figure 

 with that of the more normal pre-hallux of H. ccerulea (Plate 

 VIII. fig. 19) renders it tolerably certain that these nodules are 

 dismemberments of the main mass. 



It would be superfluous here to recapitulate the well-known specu- 

 lations and discussions which turn on the supposed ancestral con- 

 dition of the peutadactyle limb ' ; it is more pertinent to point out 

 that the evidence against the supposition that all living Amphibia 

 and Amniota have directly inherited a pentadactyle member, is, to 

 no inconsiderable extent, based upon the discovery of fragmentary- 

 cartilages in no way indistinguishable from these now under con- 

 sideration. Such fragments have been discovered flanking both pre- 

 and postaxial borders of the one member or the other in even Man 

 himself" ; and in the fertile imaginations of Bardeleben, Kehrer (24), 

 and others, we find them exalted to the dignity of lost rays. _ The 

 last-named author writes (p. 14) "so batten wir also bei der 

 Beurtheilung des Hand- und Fuss-skeletes der Wirbelthiere kiinf- 

 tighin nicht mehr von einer pentadactylen, sondern yon einer hepta- 

 dactylen Urform auszugehen, und von diesem Gesichtspunkte aus 



' For details and resume see Gegenbaur (19), and Wiedersheim (36), pp. 

 204-207 and 229-230; also " Zur Urgesch. d. Gliedmassen d. Wirbelth," ' Hum- 

 boldt,' vol. 5, 1S86. 



- Bardeleben, ' Jenaiscbe Zeitschr. fiir Naturwiss.' Bd. 19, N.F. Mi. Supplem.- 

 Heft 3, 188fi. Cf. Wiedersheim, ' Lehrbuch,' p, 224, and ' Humboldt,' cit. 



