1868.] ON PACHYBATRACHUS ROBUSTUS. 557 



2. On Pachybatrachus robmtus, a New Genus of Anurous 

 Batrachians. By St. George Mivart, F.L.S., Lecturei' 

 on Comparative Anatomy at St. Mary's Hospital. 



In examining at the British Museum the Anurous Batrachians 

 of my own collection, in order to name them correctly, I discovered 

 that the specimen here described was of a kind not present in the 

 collection, that it was also of a kind unknown to Dr. Giinther, and, 

 finally, that, as I believe, the form is hitherto undescribed. 



It appears to me to constitute a new genus, for which I propose 

 the name Pachybatrachus, and robustus as its specific appellation. 



According to the system of classification devised by Dr. Giinther 

 it must be placed in his Ranidce, where its cleft tongue, webbed toes, 

 and edentulous palate and normally placed digits approximate it to 

 Dicroglossus and Phrynobutrachus. It differs from both these 

 genera, however, in its very different habit, its larger size, relatively 

 as well as absolutely much larger and broader head and mouth, its 

 smooth skin and large tympanum. Its toes are less completely and 

 largely webbed than in Dicroglossus, while they are more so than is 

 the case in Phrynobutrachus. 



The head of Pachybatrachus robustus is very large and broad ; 

 the snout is somewhat longer than the eye ; the canthus rostralis is 

 not much marked ; the anterior end of the muzzle is rounded but 

 not insignificant in vertical extent, and the loreal region is nearly 

 vertical. The eye is rather large, and the upper eyelid is so marked 

 transversely as at first to have somewhat the appearance of being 

 free and notched behind, as in Megalixalus* ; but it is really entire, 

 and is not furnished with any process. The tympanum is very large, 

 its transverse diameter nearly equalling that of the aperture of the 

 eye. The crown of the head is nearly flat. When the head is looked 

 at from below, the upper jaw is seen to project forwards somewhat 

 beyond the anterior extremity of the mandible ; and the two rami 

 of the latter diverge at an angle of about 60°. 



There is a shght symphysial tubercle, but the outer margin of 

 each of the notches which define it can hardly be said to rise into a 

 distinct apophysis. 



The external nostrils are moderate and situated at about the pos- 

 terior end of the anterior tliird of a line drawn from the end of the 

 snout to the anterior end of the eye. 



There are no teeth in the lower jaw ; but a range of small teeth 

 runs along the maxillary border. The palate is absolutely edentu- 

 lous. The choanse are rather large, and the openings of the eusta- 

 chian tubes are of nearly the same dimensions. 



The tongue is well developed, and nearly its hinder half is free ; 

 it is distinctly notched, or rather the fleshy processes project from 

 its hinder margin, each about 01 inch in length. There is no fold 

 beneath the throat or across the chest ; but a prominent line (a glan- 

 dular fold) extends backwards, from the hinder angle of the eve- 

 * Dr. Giinther, Proc. Zool. Soc. 1868, p. 485. 



