8 



ON THK SKULL Of RAXA TIGRINA. 



floor of the luisal capsule uncovered. The outei- border presents 

 two notches, the posterior one l)ounding the posterior nares. 

 The vomerine teeth are situated in an oljlique line along the 

 posteiior border. 



The Squamosals (text-figs. 1, 3, 4, & 5, s.) are strongl}' deve- 

 loped. From the posterior half of the ci-oss-bar is given ofl' a 

 horizontal shelf-like process covering the tegmen tympani and 

 extending inwards along its posterior border as far as the 

 junction of the prootic and the exoccipital. 



The Pterygoids (pt.), Palatines (/>.), Quadrato-jugals {q.j.), 

 Maxillce (m.), bones of the lower jaw and the hyoid apparatus 

 are of the usual type. An interesting feature, however, is the 

 presence of three well-marked depressions on the ventral side of 

 the upper jaw in its anterior portion {vide text-fig. 2). The 

 middle one of these depressions is between the two premaxillse ; 

 it receives a corresponding median projection from the mento- 

 meckelians. The two lateral depi-essions are at the junction of 

 the premaxilla Avith the maxilla of each side; each accommodates 

 a strongly developed projection of the dentary of each side. 



Literature cited. 



1. NiCHOLLS, George E.^A Note on the Urostyle (o.s coccygeum) 



of the Anurous Amphibia. Pi-oceedings of the Zoological 

 Society of London, 1915, p. 239. 



2. NiCHOLLs, George E. — Some Notes upon the Anatomy of 



liana tigrina. Proceedings of the Zoological Society of 

 London, 1915, p. 603. 



3. Parker, W. K. — On the Structure and Development of the 



Skull of the Common Frog {Rana temporaria L.). Philo- 

 sophical Transactions of the Roval Society of London, 

 1871, vol. 161, p. 137. 



4. Parker, W. K. — On the Structure and Development of the 



Skull in the Bntrachia,. — Part III. Philosophical Trans- 

 actions of the Royal Society of London, 1881, vol. 172, 

 p. 1. 



