42 
MR. W. K. PARKER OK THE STRUCTURE AND 
p. 406), much like the large R. kexadactyla, but always remains small: its skull 
(Plate 10, figs. 7-10) does not suggest a specific identity with that type, of which it 
might be mistaken to be the young. A young individual of the large kind of this 
size would have a very similar skull, yet there is no reason to suppose that the two 
are identical; nevertheless, this is an arrested form. 
Besides the external characters by which this kind differs from the last— R, gracilis — 
the skull itself shows a difference of character, although on the whole the variation seen 
is very much what would be found between an adult and a young of this somewhat 
larger species. 
The occipito-otic regions (Plate 10, figs. 7, 8) are here less solid than in R. gracilis 
and much less ossified, for much of the horizontal, and nearly all the posterior canals 
(fig. 7, pr.o., e.o.) are uncovered by bone, so that the four “centres” are distinct, even 
above. The cranial “ barge ” does not widen out so much towards the postorbital 
region, and the girdle-bone (eth.) is of less extent. 
In front there is a “ prenasal rostrum,” but it is shorter, and the pro-rhinals are 
shorter and broader ; among the outworks of the nose, viz.: the upper labials ( u.R.u.l 2 .) 
we find a small sigmoid “septo-maxillary” (s.m.x.). The other more constant, investing 
bones are very similar, but the parietal region is narrower, and the parasphenoid ( pa.s .) 
is less elegant. The squamosal ( sq .) covers very little of the “ tegmen tympanithe 
“ annulus " ( a.ti /.) is even larger, and a perfect ring ; the quadrato-jugal scarcely affects 
the quadrate at all, and the hyoid cornu ( c.hy .) keeps free, above. The stapes 
(fig. 10, st.) is less, and the “columella” (Plate 6, fig. 12, and Plate 10, fig. 10) is very 
inferior in development to that of R. gracilis, yet its inter-stapedial segment ii.st.) can 
be seen to be distinct from the medio-stapedial (■ m.st .). But the form of the main 
rod is more simple and undeveloped ; the extra-stapedial ( e.st .) is a mere rounded, 
soft end of the rod, and there is no “ supra-stapedial ” band. 
The mandible is quite normal, but shows the crest on the dentary near the chin 
(Plate 6, fig. 11, d.). 
The hyo-branchial apparatus (Plate 10, fig. 9) is also quite typical, it shows, how¬ 
ever, some difference in this, that the lobes which grow out from the cerato-hyal and 
the base, are smaller. 
There are some curious points of difference between the skull of this little Oriental 
Frog and that of a young Rana temporaria of the same size ; the following are 
noticeable :— 
1. A definite prenasal rostrum. 
2. Smaller septo-maxillaries. 
3. A more arrested squamosal. 
4. A crested “ dentary.” 
5. An arrested columella, without an ascending part, and -with the distal part a 
mere bud. 
Minute, but measurable, differences are to be found between species and species, 
