194 MR. \V. K. PARKER ON THE STRUCTURE AND 



5. The 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 waU 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 annul us is veiy 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. Tlie 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. Phjlloviedusa hicolor. — Adidt female; 3^ inches long. Santarem, River Amazon, 

 lat. 2° 20' S., South America. 



Tliis (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 tlie 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 Raibie, — liaiine, that is to say, in its enducranium, 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 A\'eU developed in some 

 of the " Hyloids." Its quadrate condyles are behind those of the occiput. 



This flat, broad skull, with a smalhsh, single fontanelle and much tegminal growth 

 laterally, as well before as behind, from which grows an ethmo-nasal region one-third 

 longer than the spheno-occipital, is a curious renewal in Nature of the Skate's skull. 

 The cavity of the skidl 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 :i\vay; the wlu)le region, including 



