164 PROF. G. B. HOWES AND W. RIDEWOOD ON [Mat. 6, 



planate with these and not displaced ventrally, it follows that the 

 hind foot is here, like its fellow in front, much more normal than 

 that of Pipa. 



The calcar consists of three slender elements, the proximal one of 

 which can only represent a tarsal. 



B. PHANEROGLOSSA. 



a. DlSCOGLOSSID^E. 



Examined : — 



Discoglossus pictus : adult S , a young specimen, and a tadpole. 

 Ahjtes obstetricans : | ^ ^^^.^^ ^^ ^^^j^^ ^^^ i^^^oX^^. 

 Bombinator igneus : J ° 



Fore Foot (figs. 5, 6, 7, 9). 



Born's latest communication upon the fore foot in Ahjtes (6) 

 would be little short of revolutionary could his deductions be sub- 

 stantiated. We have already fully discussed these (p. 157), giving 

 our reasons for rejecting them in toto. 



The general plan of the carpus in these three genera is very simi- 

 lar ; in all, the largest element of the series is our postaxial centrale 

 {k), and it is in this that ossification first commences. Gegenbaur 

 has already called attention to the fact that in Bombinator it is " nicht 

 gar schwer " to see in the naviculare {n) the centrale of the Urodela ; 

 we have already given our reasons for regarding this element as a 

 preaxial centrale (p. 159). 



Gegenbaur says that in Bombinator {18, p. 17) all the carpal 

 elements are distinct ; we, however, interpret the 5th carpale of all 

 our predecessors as a postaxial centrale (p. 157). Concerning the 

 remaining carpalia we are at variance with Born ; he figures an indi- 

 vidual Alytes larva in which carpale 4 appears to have fused, while 

 still cartilaginous, with cp. 5 (our postaxial centrale) — this we have 

 never observed. He also states that in Bombinator a similar con- 

 fluence may occur between carpalia 2 and 3 while still cartilaginous ; 

 and he remarks that these variations " auf eine Neigung zum (Jeber- 

 gang in die fiir Rana, Bufo u. s. f. characteristische Carpiisform 

 schliessen lassen." We have searched most carefully for traces of 

 any such fusion, with negative results; carpalia 1, 2, 3, and 4 being 

 throughout distinct in all our specimens. Tliese elements remain for a 

 long time unossified in Alytes (fig. 9), they ossify in order 1, 4, 3, 2 ; 

 in the interval, however, between the ossification of our postaxial 

 centrale and these carpalia, the naviculare, ulnare, and lunatura 

 ossify in the order named. The following is the formula for the 

 whole series : — 



Jc. n. p. I. 1, 4, 3, 2. 



The carpal of the 5th digit is represented in all three genera by 

 the ligamentous band previously described (p. 154) ; la Alytes this 

 carries a tolerably large cartilaginous nodule, which we regard as the 

 vestige of the 5th carpale of the Urodela. 



