352 PROCEEDINGS OF THE ACADEMY OF 



may embrace species with dilated and undilated digits, e. g. Lithodytes, Fitz. 

 In Prof. Peters' genus Plectromantis those of the hinder extremity only, are 

 furnished with discs. The distinguished herpetologist, Baird, has developed* 

 an important peculiarity of most Platydactyla or Hykeformia, \ viz: the syndes- 

 mosis of the external pair of metatarsal bones (called by me 1. c. basal phalan- 

 ges.) This, however, exists in the Cystignathidse among Oxydactyla. This 

 author also employs the areolation of the abdominal integument, but Dumeril 

 has mentioned the existence of exceptions to this rule ; such are species of 

 Hylodes, Elosia and Hylarana ; so were Lysapsus, if its digital expansions be 

 regarded of primary value. Neglecting the latter point, the genus just men- 

 tioned would fall into the Discoglossidae of Giinther. The propriety of such a 

 separation from Pseudis is very questionable, for the value of difference in 

 the form of the sacral diapophyses is reduced to its minimum in view of the 

 existence of a P. mantidactyla, from Buenos Ayres, which I describe as 

 follows. It will be seen that it bears much resemblance to the L. 1 i m e 1 1 u m : 

 General form that of P. p a r a d o x a. Two vocal vesicles. Tympanum 

 nearly as large as eye. Skin of back smooth, pustulous, most so posteriorly. 

 Skin of tibia and foot minutely roughened ; several rows of acute rugosities on 

 the former. One acute cuneiform tubercle. Skin beneath entirely smooth. 

 Tips of toes very slightly dilated, brown. Above uniform light brown. A 

 yellowish band from axilla to femur ; another above it on the lumbar region. 

 Femora cross-banded with brown above and with three longitudinal brown bands 

 on their posterior face. A light band on the posterior face of the brachium. 

 The sacral diapophyses are cylindrical. Length of head and body 1 inch 6 

 lines ; tarsus to end of longest toe 1 inch 2 lines ; tibia and femur 1 inch 5 

 lines. Mus. Acad., Philada. 



Pyxicephalus ? n. sp. 



Vomerine teeth in two elevated fasciculi opposite the posterior border of 

 the iniernal nares. Ostia pharyngea smaller than nares. Tongue oval, 

 scarcely emarginate. Muzzle elevated, higher than the length of the short, 

 approximated canthus rostrales. Palpebrse prominent, thickened, covered 

 with transverse glands, broader than the interorbital space. Tympanum con- 

 cealed. Extremities short; numerous antebrachial palmar and subdigital 

 tubercles. Cuneiform process strongly developed. Toes half-webbed. Skin 

 of inferior surfaces glandular, areolated. Sides and superior surfaces coarsely 

 glandular ; a series of four or five larger glands extends from each orbit, and 

 there are two parallel rows on the occipital region. Extremities glandular. Ex- 

 panse of rami mandibuli 10 lines. Muzzle to end of coccyx 2 inches 2 lines. 

 Anterior extremity 1 inch 2 lines. Posterior 1 inch 10 lines. Tarsus 4-5 lines. 



Ground-color pale brown or whitish, with a series of large dark brown pale 

 bordered spots on the median dorsal region, and smaller spots on the sides. 

 The former interrupt a pale vertebral vitta. Three spots on each maxillary 

 region, and one between the orbits. Extremities brown spotted. No. 5825. 



If the short descriptions of the P. a m e r i c a n u s (hitherto the only spe- 

 cies) are reliable, this animal differs in the position of the vomerine teeth and 

 in coloration. 



Pleurodema b i b r o n i i Tschudi, Dum. Bibr., viii. 410. 



Pleurodema biligonigera Cope. 



Liuperus bifigonigerus Cope, Pr. A. N. S. Philada., 1860, p. 517. 



This species was described from a specimen in which the vomerine teeth and 



lumbar gland were obliterated. It differs from the bibronii, and from 



the species or varieties enumerated by Mr. Bell, in the absence of dermal 



glandules. As compared with our specimen of bibronii, the head is 



* Pr. A. N. S. Philada., 1854, p. 59. 



t Exceptions are seen in Hylarana, Potypedates and RhacophoruB. 



[Sept. 



