DEVELOPMENT OF THE SKULL IN THE BATRACHIA. 
45 
Leaving out of question mere size, form, and degree of ossification, we have only 
the following things really worthy of notice, viz. 
1 . There is no division of the upper “ fontanelle. ” 
2. There are no “ septo-maxillaries.” 
3. The “quadrato-jugal” largely ossifies the lower part of the suspensoriutn. 
4. The “ supra-stapedial ” is very short. 
5. The horns of the “annulus ” are wide apart. 
11. liana tigrina. —Adult female ; 5^ inches long. Ceylon. 
This was a large specimen, but not equal to some examined by Dr. Gunther. " In 
coming next to this kind I have passed from the smallest to the largest of the Frogs 
of India. 
As in the last, I have to be careful to distinguish those cranial characters that are 
due to mere size from those that lie deeper, and are of more impor ance. 
Of this I am certain, viz. : that although there is a special density and strength in 
the bony elements of the larger skulls, yet that is not necessarily connected with an 
extensive and generalised ossification, which, in some cases, shows most in the dwarfed 
kinds. The last species is an instance at hand, for its endocranial landmarks are 
much more obliterated than in this gigantic species. 
In the largest specimens the skull cannot come far short in size of that of Rana 
pipiens; it is a stronger structure, and the cranium proper is much larger in proportion 
to its facial outworks (compare Plate 6, figs. 1-3, with Plate 8, figs. 1-4). 
The two differ, however, in a much more important point, for this is a severely 
typical kind ; the American Bull-frog, on the other hand, is very archaic or generalised. 
Although I have taken the medium-sized Common Frog as the best typical form, 
I do, nevertheless, consider that in Rana tigrina and in the helmeted Frogs (e.g., 
Ceratophrys and Calyptocephalas) we come across the most perfect examples of 
Batrachian cranial architecture ; moreover, they are not deficient in respect of morpho¬ 
logical characters that are deeper than, and almost independent of, mere size and bulk. 
The general outline of this skull (Plate 6, figs. 1-3) is more than half of an oval, 
rapidly narrowing towards either end, as the outline of the Hen’s egg does towards 
one end. 
The whole form is broad behind, but narrowing rather rapidly forwards ; the length 
of the skull itself as compared to its greatest breadth is as 7-§ to 9, but if the 
measurement be made from one quadrate condyle to the other, as 8 to 9, for these 
hinges lie some way behind the occipital hinges. 
The ovoidal occipital condyles ( oc.c .) are well seen in both the upper and lower 
aspects, for they are large and turned over the edge of the occipital floor, so as to fit 
deeply into the atlantal concavities—a thing answering to the great strength of this Frog. 
These condyles are separated by an emarginate tract less than their own width ; 
* He gives 6 to 7 indies, mine was therefore only three-fourths the size of the largest. 
