DEVELOPMENT OF THE SKULL IN THE FEODELES. 195 



1. In the first place, the horny sheaths to the edentulous jaws (the submarginal 

 bones only, above and below, bearing teeth) make this skull unique as that of a 

 " Urodele." 



2. The peculiar form of the hind skull, throwing out falcate horns right and left. 



3. The reappearance of the ichthyic paired dermo-ethmoids, and the suppression of 

 the true nasals, the nasal roofs being arrested. 



4. As a correlate of these submesial bones, the external position of the nasal processes 

 of the premaxillaries, which are thrust apart by these bony wedges. Here the small 

 maxillaries, as in the Siluroid fishes, are both present ; they are symmetrical. 



5. The preauditory spike coming up from the parachordal plate. 



6. The short, dilated, unossified suspensorium, and the dilatation of the lower end of 

 the squamosal as moulded upon it. 



7. The confluence of an epihyal with the suspensorium, and the enlargement of the 

 stapes by the addition of a flat stalk, possibly a confluent " pharyngohyal." 



8. The arrest of the vomero-palatine bones, their sigmoid form, their elegant sigmoid 

 rows of long hooked teeth, and the entire suppression of the cartilaginous and bony 

 pterygoids. 



9. The presence of a definite prenasal cartilage. 



10. Besides the horny sheath and suppressed dentary teeth, the height, size, and curve 

 of the mandible, with its very large condyle to fit into the equally large scooped facet of 

 the quadrate. 



11. The large size of the ceratohyals, and the absence of hypohyal segments. 



12. The basihyal dilatation of the first basal piece, which carries the large first 

 branchial ; and the flat trifurcate form of the second basal piece, the proximal end of 

 which carries the second ceratobranchial, which in turn carries the third and fourth 

 arrested branchial arches. 



These twelve characters show how important a type of skull this is, and how very 

 isolated this kind of Urodele is in its own order ; also it may be pointed out that if 

 the larva of a type so far removed from Siren as Triton has some important characters 

 in common with it, and which explain it better than any thing found in the other 

 " Proteidea," the " lacunae " in this group of Amphibians must be very large indeed. 



On the Skull of the native Species of Newts. 

 A. Chondrocranium of Larva of Smooth Newt (Lissotriton punctatus), \ inch long. 



In this early stage (PL XL. fig. 1) I have shown what parts were first hardened into 

 hyaline cartilage ; this may be compared with what has been already figured by 

 Professor Huxley in Triton, and by myself in Siredcm {Yvoc. Zool. Soc. 1874, pi. 3, and 

 PhU. Trans. 1877, pi. 23). 



From this small skull we learn that the trabeculae in their hinder and more solid 

 VOL. XI. — PAET VI. No. 4. — January, 1882. 2h 



