130 MR. W. K. PARKER OX THE STRUCTURE AND 



bones is surprising when compared with what is seen in tlie large Tadpoles of cognate 

 "Ranidffi." 



The nerves figured as issuing from the skull in this view are the 1st (I.), the optic 

 (ir.), the trigemmal {Y\, V-l), the facial (VII.), with its vidian branch (VIV.) which 

 runs forwards to the upper labials ; the 8th is out of sight ; the 4th and 6th were not 

 drawn, and the 9th and lOtli (IX., X.) are indicated by their twin-passage. 



The " palato-quadrate " arch in this Tadpole is full of interest (figs. 2 and 3, 

 p.pg., pd., q.) ; it is very massive, and its hinge is opposite the beginning of the 

 terminal third of the cornua trabeculoe (c.tr.). 



Altogether these bars are twice as wide as, and much thicker than the trabeculse, and 

 every thing about them is large and solid. They are almost parallel with the skull, 

 converging very little ; the pedicle {pd.) is short, for the elbowed and forwardly turned 

 bar is of great width and takes up the room; its "otic process" {of. p.) is a rounded 

 bud overlapped by the spiracular cartilage (sjy.c). Tlie main bar becomes half its 

 former width near the pterygo-palatine conjugation (p-pg-) ', there it sends up over the 

 temporal muscle that large, outwardly rimmed scooped and sessile leaf, the " orbitar 

 process" (or.p.), which at its base has the infero-external crescentic hollow for the 

 condyle of the hyoid {hy.f.). 



As yet the pterygoid band is not free from the ethmo-palatine, but the palatine region 

 of this great arch has all its three sub-regions well marked out. The first of these is 

 that which runs into the trabecula, namely, the ethmo-palatine {p-pg-), it is half as broad 

 as the trabecula and runs outwards and forwards behind the inner nostril (/.«.). Run- 

 ning inwards in front of that passage is the pre-palatine spur [pr.pa.) ; and from the 

 wide space between the outer and the conjugating bar, in the front part of the long sub- 

 reniform orbital space, a falcate lobe of cartilage grows backwards and inwards, taking 

 up about one-fifth of the large membranous tract : this is the "post-palatine" {pt.pa.), 

 whose axis will afterwards be coincident with that of the pterygoid band with which it 

 also will be confluent. 



The distal quadrate region {q.) is more than twice as wide and thick as the trabe- 

 cuhvr cornu ; it is sinuously flat above and sub-cariuate below ; its condyle is saddle- 

 shaped, like that of a human " humerus," and looks a little inwards. 



The free mandible (Plate 22, fig. 4, mh.) is a stout phalangiform cartilage, hooked 

 externally like the " ulna," whose condyloid notch it imitates ; its distal part is solid, 

 broad, and excavated at the end for the lower labial (Id.). 



This latter segment now runs across to its fellow with but little downward bend ; 

 the two meet by a straight fibrous joint ; each piece is oblique and bulging, where it 

 fits into the end of the mandible. 



The upper labials (Plate 22, figs. 2, 3, ad.) are nearly divided from behind, forwards, 

 into two flat, oblique plates, the outer of which has a long, blunt, angular process ; 

 here the subdivision of the labial tract, right and left, takes place very early. 



The hyoid cornu (Plate 22, fig. .'5, c.hy.) is very massive, with a semi-globular 



