THE SYSTEMATIC VALUE OF RANA CHINENSIS OSBECK 71 



limbs and tibias invariably detached into blotches. 2 The hind part 

 of the thighs is whitish-grey with dark marblings; belly uniform 

 white, border of lower jaw, however, together with throat region, 

 breast, both sides of belly and thighs, slightly marbled with a darker 

 tint. The vocal sacs are blackish-grey. 



Osteological characters. The skull (Plate VI, fig. 2) presents partly 

 the characteristic marks of esculenta and partly those of R. ridibunda, 

 general form narrow and longish; becoming (gradually) narrower 

 and pointed in front, always narrower than it is long; the cranium 

 cerebrate is comparatively higher than in R. esculenta. The pars 

 faciatis of the maxillary much higher than with the esculenta. 

 Nasals narrow and meeting at a sharp angle in the middle line, join- 

 ing each other in a broad ridge, contrarily to the arrangement in 

 R. esculenta in which they are broad, meeting at a blunt angle 

 and generally not in contact on the middle line. 



The two borders of the fronto-parietals are in old examples 

 quite parallel, in younger ones slightly converging forwards; breadth 

 of their inter-orbital space measured in the middle is contained 

 3-3.5 times in its length; posterior border almost straight; upper 

 surface very slightly sunken, sutura-sagittalis always entirely ossified. 



With R. esculenta the fronto-parietals' two outer borders are never 

 parallel, becoming conspicuously narrower towards the front. 

 Their breadth between the orbits, measured in the middle is but 

 2.5-3 times contained in their length; their back edge is always un- 

 dulating; their upper surface is deeply sunken; sutura-sagittalis 

 open from os ethmoideum until about the middle. 



Tectum synoticum always triangular, whilst in R. esculenta it is 

 invariably quadrangular. 



- Prooticum always shorter and broader than in R. esculenta. The 

 tympanicum presents in its formation such differences as separate 

 most markedly the skull of R. chinensis from that of R. esculenta. 

 The forepart of the tympanicum, the zygomatic process, is straight, 

 narrow and long, just reaching the half of the longitudinal diameter 

 of the orbit, sometimes even extending rather beyond it; never 

 curved inwards, being on the contrary, always expanded in front, its 



2 Stejneger (p. 98) mentions specimens from the collection of Dr. Smith and 

 Owston, from Shikoku Islands and Mount Fuji in which the dark blotches on the 

 hind limbs melt into quite distinct crossbars. 



