194 
HR. W. K. PARKER ON THE STRUCTURE AND 
5. Tlie superorbital eave is very large and projecting, and is continued on to the 
lateral ethmoid. 
6. The nasal roof is only half the width of the floor, and the post-narial wall is very 
thick and crescentic. 
7. The inner nostril passages are very large, wide apart, and circular. 
8. The Eustachian openings are still larger, and are circular. 
9. The condyles of the quadrate and of the pedicle are very large, and the quadrate 
is partly ossified. 
10. The annulus is very large, but its horns are wide apart. 
11. The stylo-hyal and supra-stapedial are both confluent, above; the inter-stapedial 
is only segmented by osseous distinction ; and the stapes is lobulate. 
12. The mento-Meckelian is very large, and the coronoid process very low. 
13. There are no hypo-hyal nor lateral basal lobes; there is a distinct basi-branchial 
bone ; and an extra-hyal on each side. 
14. The roof-bones—fronto-parietals and nasals—are very narrow, and cover but a 
small part of the mid and fore skull. 
15. The vomers are extremely large, covering most of the nasal floor, and have a 
very solid dentigerous lobe. 
In this species, and in the next, we see, to the utmost degree, the specialisation that 
is correlated with discoid toes and fingers, and a flat, wide sacral region. 
Second genus. Phyllomedusa. 
54. Phyllomedusa bicolor. —Adult female; 3jy inches long. Santarem, River Amazon, 
lat. 2° 20' S., South America. 
This (Plate 34, figs. 7-11) is a longer skull than the last, the length being to the 
breadth as 13 to 14; this greater length is due to the unusual extent of the nasal 
region, for, if that were normal, it would be a short, broad skull. 
Here the Petromyzine embryo has metamorphosed its skull into that which is 
extremely Raiine, — Raiine, that is to say, in its endocranium, considered as free from 
bony tracts in itself, and from bony investments, outside. It fails, however, in one 
character, viz.: in not possessing a prenasal rostrum, a part well developed in some 
of the “ Hyloids.” Its quadrate condyles are behind those of the occiput. 
This flat, broad skull, with a smallish, single fontanelle and much tegminal growth 
laterally, as well before as behind, from which grows an ethmo-nasal region one-third 
longer than the splieno-occipital, is a curious renewal in Nature of the Skate’s skull. 
The cavity of the skull is scarcely longer than the closed-in tract in front of it; 
and this shallow, boat-like skull is much too large for the enclosed brain. 
The occipital condyles (figs. 7, 8, oc.c .) are posterior, project but little, are rather 
small, and are separated by a straight space equal to one condyle. The occipital ring- 
projects but little, and the arch, above, is rather cut away; the whole region, including 
