184 MR. "W. K. PARKER ON THE STRUCTURE AND 



The investing bones are sliglit, but rather strong; the fionto-parietals {f.p.) ai-e more 

 developed than in many HylcB, and creep over some considerable tract of the temples, 

 clamping the ridge of the " anterior canal " {a.s.c.). They cover in a little of the 

 exposed membranous roof {fo.), and diverge only a little to their pointed fore end. The 

 nasals («.) are crescentic trowels, that stop in front with the bony deposit, and thus 

 are far oif from the nostrils ; they are a moderate distance from each other. There 

 are no septo-maxillaries, that I can find; the other outside bones {i)x., mx., q.j., sq.) 

 have the typical development. The parasphenoid (pa.s.) is a very elegant dagger, at 

 first very wide, and then running to a fine long point. The guard is composed of two 

 long slender bars ; the handle is broad, short, triangular, and anchylosed to the skull. 



The vomers (v.) are very large, perfectly typical in form, and have an oval toothed 

 boss, they are only separated by the septum, behind. 



With an outer form more lianine than that of the species of Hjhe, this skull yet 

 shows a considerable number of specialisations that are different from what is seen 

 in a typical Frog : — 



1. The skull is more flattened out. 



2. The occipito-otic region is one continuous mass of bone, running to the front of 

 the oj)tic fenestra. 



3. The girdle-bone takes up half the anterior sphenoidal region, and half the nasal. 



4. The superorbitals are present, but ossified. 



5. The main fontanelle is open through the arrest of the roof-bones ; and the lesser 

 spaces are ossified. 



G. The pedicle is tied down by the pterygoid. 



7. The quadrate is ossified. 



8. There is no sejato-maxillary. 



9. There is neither inter- nor supra-stapedial. 



10. There is no fore lobe to the small basal plate, and the thyro-hyals are anchylosed 

 together and ossify mucli of its middle part. 



1 1 . The palatines have a cultrate ridge. 



Third genus. Nototrema. 

 52. (A) Nototrema marsupiatum. — Adidt male ; If inch long. South America. 



This skull (Plate 33, figs. 1-5) has all the massiveness of that of any stout Toad, 

 and is in extreme conti'ast with what is ibund in some of the species of Hyla — such 

 as H. phjUochroa, and //. Ewingii. It is flat at the top and wide, but is also very 

 high or deep, for a Batrachian. 



The proportion borne by the bony, to the soft, tracts of the endocranium is not 

 much greater than is common even in the genus liana, but where bone is, there it is 

 strong and rugged, and the investing bones might belong to the skull of a small 

 Crocodile, both for their strength and sculpture. 



