THE FROGS ALLIED TO RANA DORI>E. 223 



Distribution. Hills of Siam except in the south-wesfc. I 

 have altogether examined some 60 examples from the following 

 localities : — 



Khao Sebab and Hup Bon (S. E. Siam); Khao Pleung, Me 

 Song forest, Nong Bua, Me Pooan, Me Wang and Pa Meang (N. 

 Siam); Me Taw forest (N. W. Siam); Muang Liep, Huey Kan Luang 

 and Pon Pissay in French Laos on the Upper Mekong. 



The age at which the head of the male reaches its maximum 

 development is not always commensurate with the size of the frog. 

 Specimens 1551, 1564 and 3006 are fully grown, the flap is large 

 with a good free edge, and the general proportions of the head those 

 of maturity. Nos. 1559 and 5881 although also fully grown as 

 regards body length, still have the flap only as a small fold of skin, 

 while the other developments of the head are in proportion. From 

 rough observations which I have been able to make, I believe the 

 cranial enlargement commences during the third year of life. 



Eana kohchangae, sp. nov. 



Plate 9, fig. 5. 



Rana dorice, Smith & Kloss, Journ. N. H. Soc. Siam, Dec. 1915, 



i, p. 249. 

 Rana macrognathus (in part), Bouleng , Rec. Ind. Mus., 1920, xx, 



p. 51. 



Types male and female, Author's Nos. 2976 and 2985 res- 

 pectively. Collected on Koh Chang (Chang Island) in the Inner 

 Gulf of Siam, Oct. 1918. Types presented to the British Museum; 

 paratypes 2978 and 2980 to the Museum of Comparative Zoology, 

 Harvard College. 



Description of the male type. Vomerine teeth in two short 

 oblique series, commencing from the posterior borders of the choanae, 

 a little nearer to each other than to the borders of the choanae. 

 Lower jaw with fang-like projections. Head broader than long; 

 snout rounded, scarcely projecting beyond the mouth, longer than 

 the eye ; canthus rostralis obtuse, loreal region slightly concave ; 

 nostril a little nearer the tip of the snout than the eye ; distance 

 between the nostrils greater than the interorbital width, which 

 is greater than that of the upper eyelid ; tympanum very distinct, 



VOL. IV, NO. 4, 1922. 



