SKELETON OF THE AI^rEOUS BATBACHIAFS, 485 



the second copula and the ceratohyal is very narrow in all three. 

 Since a figure of the larval hyobranchial skeleton of Alytes is 

 now appearing in the ' Proceedings ' of the Zoological Society, 

 , and since the' differences heiween Discoc/lossus dixxd. Bomhinator 

 are so slight, a figure of the hyobranchial skeleton of this last 

 genus satisfies the requirements of the present communication 

 (fig- 1). 



DaCTTLETHEID^ KST> PiPIDiE. 



These two families may be shortly disposed of by referring 

 the reader to my earlier remarks on the development of the hyo- 

 branchial skeleton of Xenopus and Pipa (11. pp. 91-111). It is 

 impossible to say whether Pipa comes nearer to the Discoglossid 

 or to the Eanid type of larval hyobranchial skeleton, for no 

 copula can be distinguished, the whole cartilage being uniform 

 and continuous throughout (11. pi. xi. fig. 4). No spicula are 

 present, and the hyoglossal and laryngeal sinuses are, even in 

 this earliest stage investigated, already deep. A re- examination, 

 however, of my youngest specimens of Xenopus shows that the 

 outline of the copula (11. pi. xi. fig. 1, hJi) is more sharply 

 defined than the figure would suggest, and that a long, narrow, 

 faintly-outlined pars reuniens connects the anterior parts of the 

 ceratohyals together and involves the thin end of the copula. 

 There is nothing resembling an anterior copula, and the hyo- 

 glossal sinus is merely a small V-shaped notch. The hypo- 

 branchial part of the skeleton is reduced in size, and is wedged 

 in between the copula and the great ceratobranchial pouches. 

 It tapers to a point behind, far removed from the larynx, which 

 occupies a very posterior position. The obvious conclusion to 

 be drawn from the absence of a copula in front of the pars 

 reuniens and the union of hypobranchial cartilages behind the 

 posterior copula, is that the hyobranchial skeleton does not 

 conform to that of the Discoglossid larvge. 



List op Auxhoeities beeeered to, 



1. Boulenger, G. a. — Brit. Mus. Catalogue of Batrachia 



Salientia. 2nd ed. London, 1882. 



2. Cutiee, G. — Eecherches sur les Ossemens fossiles, t. v. pt, 2. 



Ed. 4to. Paris, 1824. 



LIN is". JOUEN.^^ZOOLOGT, VOL. XXVI. 35 



