DEVELOPMKXT OF THE SKULL IN THE BATRACHLV. 47 



Above (fig. 1), and below (fig. 2), we can trace here and there some remains of the 

 cartilage ; above, in the ethmo-palatine, the pre-palatine, and the post-palatine, on the 

 supero-external edge of the pterygoid ; below, on the end of the " pedicle," its articular 

 facet ; and above and below the graft of the quadrato-jngal ; the latter being the 

 coating of the large bilobate hinge {q.c). 



These inner works of the skull, so largely converted into solid bone, are built over 

 by very strong membrane-bones, which give the finish and the beauty to this style of 

 cranial ai'chitecture. 



Below, in relation to the skull proper, the parasphenoid (fig. 2, jxi.s.) is of the usual 

 relative size, but looks small as compared with the large bones of the face ; it is typical 

 in form, but unusually strong. 



The vomers (fig. 2, v.) here attain a very large relative and I'eal size, for they meet at 

 the mid-line (compare them with those of R. gracilis, fig. 7, v.) ; their snags are large 

 and strong, and the oblique dentigerous lobe of each is of considerable extent. 



Above, the fronto-parietals (fig. \, f.p.) form a strong roof with a notch in front, the 

 remains of the frontal suture, but are wholly coalesced beyond this ; they end, behind, 

 in two broad wings which spread over the hinder region of the cranium, almost to 

 the end. At first, hollow in the middle, in the postorbital region they develop a 

 sagittal crest, which opens out into two temporal wings. The temporal part dips 

 into the orbit (fig. 3, f.p-) and then rises over the ear-masses, moulding itself on to 

 their sinuosities. The sides are notched, and the end has a concave margin. 



The nasals in front (figs. 1 and 3, n.) form cross bars which are nearly as straight 

 as the wings of the parasphenoid ; they meet along the middle, run their pointed ends 

 far forward, ai-e triangular behind, where they overlap the fronto-parietals, and with 

 them cover the girdle-bone — all but the superorbital projections and the middle part 

 in front of the fontanelle. The fontanelles are presumably like those of the lesser 

 kinds, but they are quite covered over. 



The investing bones, outside, difier from the type in relative size and density; other- 

 wise they are quite normal : there is no septo-maxillary, the palatal ingrowths are well 

 developed, the nasal process of the premaxillaries and of the maxillaries (j)X., mx.) 

 is strong ; the quadrato-jugal {<J.J.) is grafted on to the quadrate, and the three regions 

 of the squamosal (sq.) are extremely well developed and give the highest idea of the 

 Batrachian form of these bones. So, also, the various condyles — of the occiput, the 

 pedicle, and the mandible — are well and typically formed. The mandible (fig. 3) is 

 crested both in its dentary and coronoid regions. 



The stapes and its additions are of an average size (figs. 3 and 5) ; the stapes (st.) 

 has its fore margin oblique ; jammed in between it and the feuestral edge of the 

 cjipsule there is the large seed-like inter-stapedial (i.st.) ; then, distinct from it, the 

 pistol-shaped medio-stapedial (»i.s^), whose unossified part passes into the broad 

 spatula of the extra-stapedial {e.st.), which sends upwards its supra-stapedial (s.st.) ; 

 this is ligulate, and confluent above. The stylo-hyal end of the hyoid tape is 



