DEVELOPMENT OF THE SKULL IN THE BATRACIHA. 
53 
into it, we see the postorbital process which is the curved blade ; together, they are 
half as Jong as the whole skull (see fig. 8). Also the angle at which the stem runs 
down over the massive quadrate and its condyle is very remarkable (compare figs. 3 
and 8, sq.), for the axis of the postorbital process is almost coincident with it, and 
between the stem and the supra-temporal plate the space is only half a right angle. 
The roof and floor have been wrought over the inner skull, above and below, so as to 
half hide it; thus the parasphenoid and the fronto-parietals are bony troughs or 
hollow splints. The latter ( fp .) are quite distinct, right and left, very long, narrow, 
narrowest in the middle, not very wide in the temporal region, where their edge is 
emarginate, curving with the canal below; whilst in front they are overlapped by 
the nasals (n.) and hide the girdle-bone : outside they do not hide the superorbital 
cartilages (s.oh). The nasals form a pair of large wings and are highly arched and 
strong (fig. 8); the outer part is an elegant facial hook, binding on the upper edge of 
the maxillary; the two bones meet all along, forming a nasal suture. 
The parasphenoid (figs. 7 and 8, pa.s) is a very long trough of bone of the usual 
shape, with well-formed basi-temporal wings that are trilobate. 
The hyo-branchial plate (fig. 9) is quite normal in form ; there is a slight fissure in 
the substance of the “ hypo-hyal ” lobe ( h.liy .) ; a division of the hyoid cornua into an 
outer and an inner tape not uncommon in the Batrachia : the outer is a remnant of the 
pectinate inter-branchial cartilage such as we see in the Chimeeroids and their kindred. 
Compared with the type, Rana Kuhli shows the following divergences of character :— 
1. No septo-maxillaries. 
2. Dentary with a very large tooth-shaped process. 
3. Articulation of pre-maxillaries and maxillaries very wide and high, to admit of 
the process of lower jaw. 
4. Stylo-hyal confluent, above. 
5. Extra-stapedial a very large cordate disk, peltate, and without supra-stapediai. 
6. Superorbital cartilaginous, and very distinct. 
7. Eustachian openings very small. 
I have already mentioned the peculiar form of the skull, and of certain individual 
bones, but the above are the most important morphological variations. This skull is 
altogether very instructive and suggestive ; R. Kuhli is certainly a “ borderer,” and I 
suspect it has retained some very archaic characters that have been more or altogether 
obliterated in the other species of its genus and its territory. 
c. North American (“ Nearctic ”) species. 
2 (continued).* Rana pipiens, Harr — (R. catesbiana, Shaw; R. mugiens, Merr.). 
This specimen was considerably larger than those of the Indian Bull-frogs just 
described. 
* See p. 22 where the larva of this species is described. 
