180 
MR. W. K. PARKER OK THE STRUCTURE AND 
The lateral lobes are well developed, the foremost are stalked obovate leaves, the hinder 
pair are ligulate; altogether, this is one of the most remarkable and elegant hyo-branchial 
structures to be seen in the Order. 
The investing bones are full of interest: the fronto-parietals {fp) are oblong, 
rounded, however, and scarcely dilated behind, and having a transverse dentated front 
margin ; they barely overlap the endocranium (fig. 7). Contrary to rule, they cover in 
the fontanelle (under fp), as in the larger “ Polypedatidse.” 
Over the large fore skull the nasals ( n .) are nearly as large as the fronto-parietals; 
they only touch the edges of the septum nasi (s.n.) and do not meet each other; they 
are crescentic shells, with a facial “handle.” 
The premaxillaries ( px. ) are narrow, and so is the palatine portion of the maxillaries 
{rax.), but the facial part, although extremely thin, is high : there are no septo- 
max diaries. 
The quadrato-jugals (qj.) are sharp and curved; they are wed grafted on to the 
quadrate ; the squamosals (sq. ) are wed developed, the supratemporal part is lozenge¬ 
shaped, and sends outwards and forwards a long narrow postorbital process. The 
parasphenoid ( pa.s .) is not two-fifths the length of the skull, it is a very elegant 
dagger, with backwardly bent narrow processes for the guard, and a short triangular 
handle. The vomers (v.) are long and slender; the tooth-hillocks are sub-crescentic, 
the pre- and post-narial spikes are long, and the fore part a short pointed process. 
This skull is a very exquisite structure, differing from that of the “ pattern ” rather in 
a certain dedcacy of the parts and the light airy character of the whole, than in any¬ 
thing essential; some things may especially be noticed :— 
1. There is only one fontanelle. 
2. The bones of the hind skull are confluent on the same side. 
3. There is a cartdaginous process, and also a distinct cartilage, in the fore angle of 
the orbit, above. 
4. There is a short prenasal rostrum. 
5. There are no septo-maxidaries. 
6. The girdle-bone has its sides partly formed of ossified membrane. 
7. There is a short hinder projection from the basal plate, and some enclostosis there ; 
and the whole of that apparatus is very remarkable in the shortness of the plate, the 
depth of the front notch, and the great length of the arcuate thyro-hyals; but these 
things, and many more, which the figures will show, are almost undefinable modifica¬ 
tions of the typical form, and this Tree-frog is just such a refinement, so to speak, of 
the typical Frog, as that is of the Common Toad. 
50. Hyla -? sp.—Tadpole, 1 inch long; hind legs, 5 lines. Bio Janeiro. 
These, and the skulls of more advanced larvae of Nototrema marsupiatum (Plate 30, 
figs. 8, 9, and 10-13), show that the modification of the larval Batrachian chondro- 
