DEVELOP]\rKNT OF THE SKULL IN THE BATRACHTA. 145 



Here the whole structures is very Ranine, but unusually ntirrow Iroui side to side, 

 yet the form of the palatines and pterygoids {pa., pg.) and the amount of unossified 

 cartilage is quite normal ; as also is the pedicle (i^c/.), but the quadrate (7.) is partly 

 ossified by the quadrato-jugal ('/.,/.)■ 



The Eustachian openings {eu.) are quite as large as the inner nostrils ; they are oval, 

 and are turned outwards and forwai'ds. 



The annulus {a.tij) is large and complete, and the stapes and columella (figs. 1 and 2, 

 St., e.st.) are like those of P. maculatus; the stylo-hyal {st.h.) is confluent above. The 

 mandible and hyo-branchial apparatus (figs. 3, 4) are normal, but the articulare («r.) is 

 fastening upon the ossifying cartilage to make a more solid lower jaw than that of 

 most species; also the hypo-hyal {h.hy.) has a free lobe in front, as in the "norma," 

 which is not present in P. maculatus. 



Tliat species approaches Rhacopliorua maxiinu.s ; this comes very near ITi/larana 

 temporalis (Plate 29, figs. 1-5). 



The investing bones only differ from the type in being fitted to a skull with a wider 

 cavity and narrower cheeks. 



As regards conformity to the Batrachian type, this kind is one of the highest : — 



1. The whole cranio-facial structure is longer, and with a broader skull-cavity. 



2. The occipito-auditory bones are all confluent, right and left. 



3. The columella has an imperfect supra-stapedial. 



4. The cartilage both above and below the mandibular joint is partly ossified. 



5. There are no septo-maxillaries. 



On the whole, this is perhaps the least modified from the typical Ilanine skull of any 

 of the "Platydactyla." 



3G. Pohjiyedates maculatus. — Adult male; 2 inches 1 Hue long. India. 



There are two noticeable varieties of the Oriental Polypedatidaj, namely, those 

 with short and flat, and those with long and narrow skulls ; tliis (Plate 27, figs. 1-4) 

 belongs to the first variety, which culminates in Rhacophorus maximus (Plate 26, 

 figs. 5-9). The outline is evenly semi-elliptical ; the length is to the breadth as 8 to 9, 

 and the condyles of the quadrate come short of those of the occiput by one-thu-tieth of 

 the w^hole length of the skull. 



The term Hijlarana given to one of the genera in this Family perfectly expresses 

 the relationship of this group, whose members are almost exactly intermediate between 

 the species of Rana and the species of Hyla. 



In this skull the antero-posterior extent of the nasal and orbital regions is equal, 

 but that of auditory, only one-half ; this latter region, however, is of great transverse 

 extent. 



The chondrocranium, as a whole, has had a fair half of its bulk converted into bone, 

 and the skull in all respects has a medium strength ; it is much depressed, and the 

 orbital region is at least one-third wider than in most of the species of Rana. 



MDCCCLXXXI. u 



