1918.] BaIiM Prashad : Middle Ear of Indian Frofjs. 101 



mella is visible as a distinct nodule raising up the skin. The tympanic 

 membrane is quite a distinct structure underneath the skin. 



Rana. — The tympanum in most species is distinct, but in a few may 

 be hidden. The condition in R. ligrina has been described in detail. 

 In R. liebigii^ the tympanic area is not distinct, but the tympanic 

 membrane is seen to be quite a distinct structure lying- under the skin. 



Micrixalus. — The tympanum may be indistinct or hidden. In 

 a large series of specimens of M. silvaticus of different ages it was seen, 

 that the tympanic area is quite distinct in the young, becoming in- 

 distinct in older specimens, and in the fully adult it is not to be dis- 

 tinguished. The tympanic membrane is quite a distinct structure. 



Nyctibatrachus. — The tympanum in this genus is described as 

 hidden. In some well preserved specimens of N . major the tympanic 

 area was distinctly marked off as a light-brown patch of skin ; in the 

 other poorly preserved specimens however it was not distinct. 



Nannobatrachus. — The tympanum for this genus also is described 

 as hidden. The condition in specimens of N. heddomii examined was 

 the same as described for Nyctibatrachus inajor ; and the distinctness 

 of the tympanic area depended largely on the condition of preservation. 



Rhacophorus. — The tympanum is usually distinct. In 7^. maxi- 

 nms it is distinctly depressed and is overhung on the upper side by a 

 fold of skin, which makes the structure very prominent. 



Ixalus. — The tympanum may be distinct or hidden. In the two 

 species 7. glandidosus and I. leucorhinus, examined by me it was quite 

 distinct. 



Family Engystomatidae. — This family is peculiar in having the 

 tympanic area shifted to a much more forward position than in the 

 Ranidae ; it lies quite close to and at a much lower level than the eyes, 

 in some it lies just below the eyes. 



Calophrynus. — The tympanum is distinct. In C. pleurostigma 

 tympanic area was found to be definitely marked off, and covering 

 over the tympanic membrane lying under it. 



Microhyla. — The tympanum is described as hidden. In specimens 

 of M. rubra examined by me the condition (fig. 10) was the same as in 

 Calophri/nus described above. 



Kaloula. — The tympanum according to Boulenger is hidden. In 

 three specimens of K. obscura, the tympanic area was not a distinctly 

 marked off portion, but in two better preserved specimens it was quite 

 distinct. In K. fulchra (fig. 9) the tympanic area was slightly depressed 

 and so better marked. 



Cacopus. — The tympanic area in specimens of C. systoma is quite 

 indistinguishable externally (fig. 7) but on removal of the skin (fig. 8) 

 the tympanic membrane is seen to lie under the skin quite close to the 

 eye. 



Glyphoglossus. — The tympanum is described as hidden. In two 

 well preserved specimens of G. molosus the tympanic area was seen 

 as a slightly depressed circular area with raised edges, and lying just 



^ Dr. iVnnandale informs me that there is a very great confusion about this species, 

 several species being confused under the name, but the form referred to is the true 

 B. liebigii, Gthr, 



