DEVELOPMENT OF THE SKULL IN THE BATRACHTA. 247 



13. The solid basi-branchial bone. 



14, The variation in some of the investing bones — 



a. Breadth of fronto-parietals. 

 h. Great size of nasals. 



c. Feeble upper part of the long squamosals. 



d. The gi-eat breadth of the parasphenoid. 



e. The thin, shell-like, toothless vomers. 



All these tilings seem to prove tbat Callula is far removed from the typical 

 Batrachian. 



Second Family. Hylaplesid^e. 



Ear perfect ; toes free ; sacral apophyses cylmdrical ; no parotoids. 



Genus Hykqjlesia. 

 73. Hylaplesia tinctoria. — Adult female ; Ij inch long. South America. 



This is a long skull (Plate 44, figs. 1-7), the breadth being, contrary to rule, less 

 tban the length, or as 8 to 9. Its cheeks are very feeble, slightly bowed, but the 

 cranium itself is very broad, and altogether forms an irregular oblong. 



The quadrate condyles have only got as far back as the space between the Eustachian 

 openings and the stylo-hyals (figs. 2 and 3, q.c, eu., st.h.). The breadth across the 

 ethmo-palatines is three-fourths that across the quadrate hinges. The breadth across 

 the ethmoidal wings, excluding the ethmo-palatines proper, is but little less than the 

 breadth of the roof at the temporal angles ; the roof is lessened very little, forwai'ds ; 

 its orbital edge is gently sigmoid, as it naiTOws from the temples, then widens, and 

 narrows again in front. The muzzle is by far the broadest I have seen ; yet the 

 nasal region is of normal length — or antero-posterior extent ; but the breadth is just 

 twice as great, so that the terms should be reversed. As in several of the " Caduci- 

 branchiate Urodeles," the endocranium is one continuous bony trough, for cartilage 

 only remains as the occipital condyles [occ.) ; as the tegmen tympani (fig. 1, t.ty.) ; the 

 facet for the pedicle {pd-) ; as a circle round the very small optic fenestra (IT.) ; and in 

 the fore and under parts of the transverse muzzle {px., s.n.). The strength of the 

 cranium is in great contrast with tlie weakness of the face ; in the former, anchylosis 

 has obliterated most of the landmarks, yet the fronto-sagittal suture is only lost behind 

 (fig. l,/i>.-^^ 



I can only do justice to this abnormal skull by comparing it with those of the two 

 " Aglossal" types, Pip>a and Dacti/Iethra (see Phil. Trans., 187G, Plates 5G-62). 



As to the skull, there is no type amongst the tongue-bearing Frogs and Toads equal 

 to this for softening down the hard distinction between them and the two tongueless 

 " waifs" that make up the sub-order " Aglossa." 



• This sntnre is too sti-ongly marked, behind, in tlie figure, and .so also is the slight ridge along the 

 ethmoid. 



