1920.] G. A. Boui.ENGER : Frogs of (he Genus Rana. 



51 



16. Rana macrognathus. 



Raita doriae. part., Bouleiiij., Ann. Mas. Genova. (2) XIII, 189,^. p 32S, pi. 



\iii. tig. I, and Faun. Mai. Pen.. Rept. p. 231 (1912). 

 Rana macrognathus, Bouleng., Ann. and Mag. N.H.. (8) XX, 1917, p. 



414. 



I now regard as deserving specific distinction a frog from 

 Upper Burma in wliich the males differ from those of R. doriae in 

 the very large head with strong swellings formed on the lower sur- 

 face of the mandible and on each side of the occiput, by the extra- 

 ordinary development of the masseteric and depressor muscles, and 

 in which a strong pointed tooth-like process is present on each side 

 of tlie mandible near the symphysis, as in R. macrodon and R. 

 kuhlii. In these males, when fully developed, the interorbital re- 

 gion is broad and very convex, the swelling produced posteriorly as 

 in Pdobates fuscus ; the frontoparietal bones are raised in their 

 anterior half, rugose though free from the skin, and furnished 

 with three strong longitudinal ridges which unite into a single one 

 on the posterior part of the bones. The tympanum of these males 

 is nearly or quite as large as or even larger than the eye. Females 

 are hardly distinguishable from R. doriae. The length of the inner 

 metatarsal tubercle is i to f the length of the inner toe. The 

 warts on the back are often more prominent than in R. doriae. 



Measiireinenis in millimetres. 



4. Da Ban, S. .\nnam. 



Ok Yam, S.E. Siam. 



I — 3. Karin hills (types). 

 6. Koh Chang Id., Siam. 



This frog is intermediate between R. doriae and R. pileata. 



The types are from the Karin Hills, 1300 to 1600 feet, and 

 from the district of the Karin Bia-po. I have received from Dr. 

 Malcolm Smith a specimen from Annam. Small specimens from 

 Siam (Ok Yam, Koh Kut Id., and Koh Chang Id.) appear to 

 belong to the same form, but the male, although showing the large 

 tympanum and the tooth-like processes of the lower jaw, lacks the 

 swelling on the interorbital region. 



