6o 



ANURA 



the ventral wall of the body ; the anus opens at the end of a 

 somewhat protruding tube, either in the median line, just in front 

 of the ventral fin (Discoglossidae, Pelobates, Bufo), or it assumes 

 an asymmetrical position by turning to the right side (Hyla, 

 Hanoi). 



Although both pairs of limbs begin to bud simultaneously, or 



FIG. 11. Tadpoles of Megalophrys montana from Bukit Besar, Malay Peninsula, x 3. 



the fore-limbs even earlier, the hind-limbs are hurried on, and 

 appear first, long before the fore-limbs. The latter lie ready 

 beneath the skin of the gill-chamber, and the right always breaks 

 through the skin, while the left does the same in the Medio- 

 gyrinidae, while in the Laevogyrinidae it is generally pushed 

 through the left- sided spiracular opening, immediately behind 

 the outer gills. According to Barfurth the right limb appears, 

 in about 80 per cent, of Rana esculenta, from two to eight hours 

 before the left. 



