DEVELOPMENT OF THE SKULL IN THE BATRACHTA. 
215 
The thyro-hyals are long and straddling, with much cartilage at the end, and on the 
left side there is a round nucleus of cartilage (; t.liy'.) outside the bone, proximally. 
Just behind the front lobes a band of endostosis runs across the plate—a faint attempt 
at the formation of a bony “ 1st basi-branchial.” 
The investing bones are coarse and strong but limited in their superficial extension. 
The fronto-parietals (fig. l,f p.) are roughly radiated, grooved externally, and pitted 
in the hind part, where they very imperfectly cover the hind skull. 
Their oblique temporal groove is inside the combined arches of the anterior and 
posterior canals (fig. 1, cat.), and their ragged expansions are anchylosed to the prootics 
within. They are mere thick bars on each side of the naked fontanelle, and overlap 
the girclle-bone (etli.) in front. The nasals (n.) are large, long-handled below, and do 
not quite meet over the septum-nasi. 
The premaxillaries ( px.) are gently arcuate, of great extent, and have well developed 
nasal and palatine regions. 
The maxillaries ( mx .) are also well developed, with a considerable palatine edge that 
broadens behind before it gives off its jugal process; there is between these bones a 
small angular septo-maxillary ( s.mx .). The quadrato-jugal (qj.) is a short curved 
spike, partly confluent with the quadrate (q.). 
The squamosal (sq.) has a rough, short upper, and a gently expanding lower, limb. 
The parasphenoid (pa.s .) has all its processes well developed, it is quite Bufonine, 
narrowing rapidly in front, and with very extended lateral processes that run to a 
point; the handle is large and notched behind ; and the opposite process, under the bone 
at its basi-temporal part, is an extended oblique toothed ridge. 
The vomers (fig. 2, v. ) are small, with a prenarial hook, a hooked fore part, and a 
notched hinder process. 
In this skull the Bufonine characters are arrested and modified : this is especially 
seen in the deficiency of the roof bones, in the continuousness of the palato-suspensorial 
cartilages, and in the perfect freedom of the pedicles. It, therefore, is not so 
different from a Frog’s skull as that of its congeners. 
From the “norma” it differs in—- 
1. The general strength and coarseness of its structure. 
2. There are no secondary fontanelles. 
3. The main fontanelle is uncovered. 
4. There are no dentigerous bones. 
5. There is a superficial (“ parosteal ”) palatine. 
6. The pterygoid is most developed below, and not above, 
7. The mandible is unusually cartilaginous. 
8. There is no inter-stapedial; and the supra-stapedial and stylo-hyal are confluent 
above. 
