DEVELOPMENT OF THE SKULL IN THE BATRACHIA. 05 



almost to the pvootic and parasphenoid. The angle of the fork is somewhat rounded, 

 so that the large Eustachian opening (eit.) is sub-triangular. The bony plates {2M-,2>9-) 

 are normal, but thin and lathy. 



The quadrate region or outer fork is very long, and retreats as far back as the 

 middle of the stapes : this is one of the deepest cheeks to be found in the gi'oup. The 

 cartilage is very slightly ossified by the quadrato-jugal {q.j.); the condyles (q.c.) have 

 the peculiarly elegant form seen in the Oriental Ranee, viz. : a very large, long, postero- 

 internal trochlea, and a rounded, small, antero-external convexity. 



The annulus (fig. 3, a.ty.) is rather large and perfect, as in the congeners of this 

 species ; the stapes {st.) is large, oval, and umbonate. The medio-stapedial {m.st.) has no 

 proximal intervening segment cut ofl:', the extra-stapedial (ciit.) is spatulate, and the 

 supra-stapedial is confluent above. 



The mandible (fig. 3) is normal, the condyle (ar.c.) is long and subreniform. The 

 stylo-hyal (fig. 2, st.h.) is narrow at fii'st and confluent ; it w^idens gradually up to the 

 hypo-hyal bend below (fig. 4, c.hy., h.hy.) ; over the curve there is now a small thin 

 extra-hyal {e.hy. for exJuj.). The notch in front of the basal plate is wide, and the 

 whole structure is normal ; the front lateral lobes are now fan-shaped, and. the hinder 

 hgulate. The thyro-hyals {t.liy.) are large and bent outwards. The investing bones are 

 very thin and splintery; the fronto-parietals {f.p.) are feeble and arrested in front; the 

 nasals (h.) are feeble and ragged, like the newly-formed osseous centres of a young 

 specimen ; the premaxillaries (_px.) are wide and well developed as to their processes ; 

 there is a pair of small seed-like septo-maxillaries [s.mx.). The maxillaries {mx.) are 

 high, but thin ; they are notched in front where they overlie the angle of the nasal 

 floor, and have a bilobate ascending plate ; they stretch along more than half of the 

 temporal space behind. The dentiform quadrato-jugals {q.j.) are only slightly grafted 

 on to the quadrate ; the squamosals {sq.) lie well over the narrow tegmen, and have 

 a shortish diamond-shaped postorbital process. The descending bar (fig. 3, sq.), is of 

 great length, and widens gradually downwards. 



The parasphenoid (fig. 2, pa.s.) is quite Ranine, and its basi-temporal plates are very 

 large and bilobate externally. The vomers {v.) are Cystignathine ; of the three spurs 

 the foremost is twice the size of those which fence m the inner nostril {i.n.) ; the body 

 is oblique, arcuate, almost reaches the middle, and is armed with an almost straight 

 crest of teeth ; the two crests form somewhat more than a right angle, but their sharp 

 outer end is strongly turned forwards. As compared with that of our Native Frog, 

 this skull is — 



1. Much broader and deeper. 



2. The hinder centres of the endocranium are smaller, and the girdle-bone is larger. 



3. There is only the main fontanelle, which is rather small. 



4. The parotic wings are extremely outstretched. 



5. The interorbital region is very narrow in front. 

 G. There are distinct superorbital " eaves." 



MDCCCLXXXI. K 



