AN ABNORMAL FROG. 89 



relation to the distal tarsal bones : its size is just that of the 

 normal calcar ; and, in addition, in dissecting the foot I found 

 that its muscles corresponded exactly with the account given in 

 Gaupp's Ecker-Wiedersheim's 'Anatomie des Frosches' for the 

 musculature of the calcar. 



One of the most interesting points in connexion with this 

 abnormality is the fact that in the manus of the frog there are 

 always only four digits, and the one usually accounted absent is 

 again the first of the series, though Emery (Anat. Anz. Bd. v. 

 1890, pp. 283-288; and elsewhere) has claimed that the missing 

 finger is really the fifth. But whether the absence of the first 

 digit from the hind feet of the abnormal specimen can be regarded 

 as additional evidence tending to disprove Emery's theory, or not, 

 I cannot say. Another point of theoretical interest lies in the 

 presence of the calcar despite the absence of the hallux, which 

 seems to me to afford considerable support to the view that 

 the former does not belong in any way to the digital series. 

 Theoretical consideiations based upon a single specimen are far 

 too doubtful, however, to render it worth while attempting to 

 discuss these questions. 



Among the gi-eat number of structural abnormalities which 

 have been described for frogs of various species, a number of cases 

 of polymely and polydactyly occur ; but apparently this specimen 

 is the first in which a variation of this kind has been recorded. 



