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ZOOLOGY OF THE FAR EAST. 
tubercle of the fourth. There is a well-developed external metatarsal fold but no 
trace of an external metatarsal tubercle. The web of the foot is practically complete, 
extending at least as far as the base of the terminal phalanx in all the digits. When 
the foot is stretched out the margin of the web is slightly convex between the fourth 
and fifth toes. The internal metatarsal tubercle varies greatly in size and shape but 
the variation seems to be individual rather than racial, for extremes, which are not 
correlated with other differences, occur at many or all points in the geographical 
range of the species. 
The skeleton of R. tigrina has recently been described by Nicholls. I have been 
able to confirm his observations on most of the bones by an independent exam- 
ination. 
The colouration of the living frog is characteristic, especially in the young, for 
Fig. 2. — Mouth-disc of tadpoles of the R. tigrina and R. limnocharis groups. 
A. — R. tigrina ( x 14). B. — R. limnocharis ( x 18). C. — ? R. brevipalmaia ( x 10). 
in the adult some of the distinctive markings become obscure. The dorsal surface is 
green in the male and yellowish in the female, the sexual differences appearing at an 
early age. In the young of both sexes a black bar extends forwards from the eye 
through the lower edge of the nostril to near the tip of the nostril, but the bars of 
the two sides do not quite meet. Below this bar there is a broader and usually some- 
what irregular white stripe extending below the eye from the tympanum to the end 
of the snout, and below this again the edge of the upper lip is white, sometimes with 
irregular vertical black bars. The lower lip is white with rather broad, scattered 
black bars. All these markings tend to disappear in preserved adult specimens, though 
they can usually be traced even in large fresh specimens. A pale mid-dorsal stripe is 
usually, but not always present and has a much more permanent character. Large 
blackish spots, often with a dead black margin, and surrounded by a faint pale halo 
