132 JIR. w. K. PARKER ON THE STRUCTURE AND 



This skull (Plate 24, figs. 1, 2) is short, flat, and a very delicate semi-osseous 

 structure altogether ; the length is to the breadth as 5 to 6, and the quadrate 

 condyles (q.c.) reach as far back as the fore edge of the stapes. The occipital 

 condyles (oc.c.) are large, separated by a very gentle emargination of the basal plate, 

 and directly posterior in aspect. 



The auditory regions are gi-eatly winged outwards, becoming narrow externally; the 

 common occipito-auditory bones are single on each side, reach as far out as to the 

 wings of the parasphenoid below, and touch the narrow squamosal above ; thence 

 the outside of the vestibule (vb.) and the tegmen tyrapani {t.tij.) are left soft. 



So also is a rather wide tract above and below at the middle ; whilst in front the 

 prootic region of the bone reaches the foramen ovale (fig. 2, V.), which it half encloses. 

 The optic fenestra (II.) is large, and is well surrounded by cartilage, and this cartilage 

 is continued beyond the middle of the orbital territory ; two-fifths of this territory 

 only is taken up by the girdle-bone (eth.) This bone just reaches the "wings" and the 

 fore end of its own proper territoiy, and above (fig. 1, eth.) it is imperfect ; the right 

 and left half, which are united, but leave emarginations below (fig. 2), are not fused 

 above : their horns just meet in the fore margin of the anterior fontanelle (/o.). The 

 "tegmen cranii " is very short in the ethmoidal region ; it forms a flat and widish wall- 

 top, runs a band across the roof in the postorbital region, and becomes superoccipital 

 in front of the middle of the auditory regions, right and left. The main space thus 

 spanned is divided into two fontanelles {fo.,fo.) ; the front space is one-third larger 

 than the hinder, and is emarginate behind; the hinder space is transversely oval. This 

 is a rare modification ; behind, there are, as a rule, two secondary spaces, and in 

 several types none. 



The tegmen grows out into a small superorbital " eave " in front, and then there is 

 a wide stretch of cartilage — ethmoid and ethmo-palatine. Outside the small super- 

 orbital projection of the "wing" there is a very large superorbital cartilage {s.oh'.) ; it 

 covers nearly a third of the orbital space ; is roughly oval, its large end foremost, and 

 it is placed obliquely, with its hollow face downwards. This is also a rare character, 

 it occurs in Phyllomedusa hicolor ; but in that type it is much smaller. The common 

 septum of the ethmoidal and nasal regions (fig. 1, *•.».) is large, and is continued in 

 front as a prenasal rostrum (p.n.). As in Bomhinator the alse of the nasal roof (fig. 1) 

 are very little develojied along the sides of the septum, the cartilaginous pouches 

 being nearly all in front, lying on, and coalesced with, the " subnasal lamina;." These 

 plates (fig. 2, s.n.l.) are normally wide, and have long narrow pro-rhinals (p.rA.). 



The muzzle being very obtuse, the nostrils are wide apart, they are protected by 

 the usual inner and outer labials (u.P.u.P.), which are large and well developed. 



The palato-suspensorial arches are wide apart, and the orbital spaces are oval, the 

 pre-palatine spike {pr.pa.) is large, the stem (e.pa.) wide, and the post-palatine and 

 pterygoid tracts are but little affected by the jDalatine and pterygoid bones {pa., jyj-), 

 which are quite typical. This cartilage is seen in both forks— the pedicle (pd.) and 



