94 
MR. W. K. PARKER ON THE STRUCTURE AND 
The roof bones ( f.p .) are strong, well developed behind, where they rise over the 
arches of the canals (figs. 1 and 3), have a small temporal wing, and are short and 
rounded in front, where they leave the girdle-bone uncovered, scarcely covering the 
great fontanelle. 
Also between the temples there is a small gap which answers to the “ parietal fonta¬ 
nelle ” of a Lizard; the orbital flange of each bone (fig. 3 ,fp.) is thickish, and very 
irregular in outline. 
O 
Answering to the large size of the cartilaginous ethmo-palatines the nasals (n.) are 
huge bones, the left much the larger of the two, and sending an angular process over 
the fronto-parietal. Their fore part is pointed and divergent, their facial or descending 
region thick ribbed and projecting; their top is strongly convex. 
The premaxillaries and maxillaries (pc r., mx.) are quite Ranine ; they are strong and 
well developed. The septo-maxillaries (s.mx.) are small and inconspicuous. 
The quadrato-jugals (q.j.) are grafted on to the quadrate ; they are strong, arcuate, 
tusk-like bones. 
Also the top of the squamosal (sq.) is like a tusk, being curved, and turning inwards 
in front as a sharp fang ; the supratemporal part is of small extent, and the descending 
plate long and broad. 
The parasphenoid (fig. 2, pa.s.) is perfectly normal ; it is large and swelling, has 
a long point in front, its wings bent backwards, and its handle triangular. 
The vomers (fig. 2, v.) are large, many-cornered bones ; they bind crescentically 
round the inner nostrils ( i.n .), which are large, circular, and very wide apart. The 
front process of the bone is small, not reaching nearly to the end of the subnasal 
angle; the terminal plate almost touches its fellow, is a fan-shaped tract, and ends in 
a thick crescentic ridge, turned obliquely outwards and backwards, and armed with an 
arched row of sharp teeth. The nasal valve-cartilages (u.l l .u.l 2 .) are well developed. 
This skull differs from that of a true Rana in :— 
1. The epiotic growth. 
2. The pterotic growth. 
3. Its widening roof forwards. 
4. The huge etlimo-palatine. 
5. The additional palatine bony crest. 
G. Absence of an inter-stapedial. 
7. The small extent of, and bony tract in, the basal plate. 
8. The large size of the nasals, and their want of symmetry. 
20. Cystignathus - \ sp.—Larva ; 1 inch long ; tail, § inch ; hind legs, 1 line. Lake 
Jannarg, Manaoo, Brazils. 
This larva of a Neotropical Frog belongs, evidently, to the same genus as the last; 
it is less than a third the length of the large Tadpole, whose skull has just been 
described, and in development it is intermediate between the last two. 
