DEVELOPMENT OF THE SKULL IN THE LTIODELES. 209 



11. The occipital condyles are subpedunculate, and separated by a large notch for 

 the " odontoid rudiment." 



12. The halves of the endocranium are only united in front and behind by a very 

 narrow tract of cartilage ; most of the basal plate behind, both trabecular and para- 

 chordal, has been absorbed ; but, right and left, cartilage is seen on the occipital con- 

 dyles, the stapedial operculum, the basipterygoid facets, and in the alisphenoidal walls. 



13. The unossified nasal roofs are wide apart, right and left; but they have coalesced 

 with the cornua trabeculse and the ethmopalatines. 



14. Besides its condyle, the suspensorium has much cartilage above; and its narrow 

 pterygoid foregrowth is only partially incrusted into bone ; it has no part severed from 

 its root. It is confluent above ; but the pedicle and otic process are free : the direction 

 of the suspensorium is unchanged ; it looks forwards as well as downwards and out- 

 wards. 



15. Between the nasals above, and the vomers below, the " middle nasal passage" is 

 permanently visible. 



16. The articulo-Meckelian rod is only partially converted into bone, and that mostly 

 on the upper part. 



17. There is no epihyal or pharyngohyal element; therefore, as a correlate of the 

 early closure of the tympanic (first) cleft, there is no columella attached to the stapes ; 

 and as there is no rudiment of a cochlea, there is no fenestra rotunda. 



18. There are no hypohyals; the ceratohyals are large and ossified in the upper 

 narrower part. 



19. The branchial apparatus is reduced to a semiosseous first basibranchial ; the 

 second becomes entirely absorbed in old age — a first arch with an ossified epi- and 

 cerato-branchial, and an unossified, shrunken, second cerato-branchial. 



Many curious minor modifications take different places in " Caducibranchs," as I have 

 shown in my papers in the ' Philosophical Transactions ' (1877, pis. 21-29, pp. 529-597) 

 and the 'Transactions' of the Linnean Society (new series, Zool. 1880). 



But the most important modifications of the skull in this, the highest, division of the 

 Urodeles have been described and figured by Wiedersheim in his invaluable works. 



The Skull of the Adult Triton cristatus compared with other Types. 



The skull of the Common Warty Newt, like that of our native Frog, serves well for 

 a pattern to measure others by ; it is more transformed than that of an adult Spotted 

 Salamander, which retains a postclinoid band of cartilage, and exceptionally, like Siren 

 lacertina, has a prenasal rostrum. 



Some types of the " Caducibranchs " have a small columella, as I have shown, -^dz. in 

 Spelerpes and Desnwgnathus (see Trans. Linn. Soc. 1880, pis. 18, 20, 21) ; and others, as 

 Ellipsoglossa nmvia, Banodon sihiricus, Besmognathiis fuscus (Wiedersheim, op. cit. 

 pi. 5), have, like Sieboldia, an epihyal rudiment confluent with the hinder margin of 



