70 Zoological Society : — 



other ; and therefore I refer first to tlie niore-knov,n structure of ear, 

 and propose for the present the following division of this group : — 



I. Aglossa with united eustachian tubes and entirely bony cavum 



tympani. 



a. With maxillary teeth : DactylethridcB. 



b. Without maxillary teeth : Pijndce. 



II. J'// I'os^ft with separated eustachian tubes; cavum tympani? 



a. With two horizontal fangs in the intermaxillary bone : 

 Myobatrach idee. 

 Finally, of the last group of Proteroglossa only one genus is 

 known, forming the type of a family — Rhino phrynidx, the com- 

 plete characters of which would be — 



Proteroglossa loithout maxillary teeth, tvith imperfectly developed 

 ear, paratoids, dilated diapophysis of sacral vertebra, and 

 webbed toes. 



Bibron has given the only published description of Rhinophrynus 

 dorsalis ; but having had only a single specimen in an imperfect 

 condition, he was not enabled to point out all its peculiarities. I 

 therefore finish this paper with a full description of it. 



The body being of an oval depressed shape, appears to be broader 

 than it in reality is, because the skin is too wide for the circum- 

 ference of the body, forming on each side a broad longitudinal fold. 

 It is rounded on all sides, the belly being rather more flat ; the whole 

 surface smooth, only in some places finely granulated. The head is 

 confounded with the body, situated on the same level, and appears 

 to be only the tapering front part of it ; being somewhat depressed, it 

 tapers conically, and ends suddenly with the obtuse, truncated top of 

 the muzzle. The front part of the muzzle forms, if closed, a flat round 

 disk, somewhat similar to the snout of a pig, but differing by being 

 separated by the cleft of the mouth into an upper smaller and a lower 

 larger half. The mouth itself is so peculiarly formed as to be unlike 

 that of eveiy other Batrachian. The cleft is situated in one plane, 

 not on the lower side of the muzzle, but above the middle ; and if the 

 snout be imagined to be a truncated cone, the cleft spHts'it by a ver- 

 tical cut going from the truncated plane to the base ; the cleft there- 

 fore does not form a convex line, but three sides of the vertical cut 

 of a truncated cone. Being of itself not small, and reaching nearly to 

 the anterior angle of the eye, it does not allow a considerable widen- 

 ing of the mouth, as is necessary where a sling-tongue is present ; 

 and when we consider this configuration connected with the plump 

 figure of the animal, we may conclude that its food consists only of 

 small and slow animals. The nares are situated on the upper side 

 of the head, at some distance from the end of the snout ; they are 

 formed by a small oval opening, surrounded by a low cutaneous fold, 

 and can probably be closed. The eyes are situated but little fur- 

 ther behind the nares, but rather more outwards; they are small, 

 and placed behind a narrow cleft formed by the swollen external 

 eyelids. 



