SKULL 



17 



A pair of prefrontal bones is present in most Salamandridae, 

 e.g. Salamandra, Triton, Amhlystoma, especially in the larva, and 

 in Cryptohi'arichus ; these bones are absent in Amphiuma, Necturiis, 

 Proteus, and Siren. 



The lacrymalia are still separate in i^ome Amblystomatinae, 



Fig. 3. — Skulls of various 

 Urodela. 1, Salamandra ma.- 

 culosa, ventral view, and 2, 

 dorsal view ; 3, Axolotl stage of 

 Amhlystoma ; 4, adult stage of 

 Aviblystoma ; 5, Salamandrinc 

 perspicillata (after Wieders- 

 lieim) ; 6, Salamaiidra ma- 

 culosa, dorsal view of the lower 

 jaw. .1, Articulare ; Cj, C^, 

 outer and inner occipital con- 

 dyles ; C'h, choana or posterior 

 nasal opening ; d, dentary ; E, 

 ethmoid ; F, frontal ; LO, 

 lateral occipital ; M, maxillary ; 

 N, nasal ; iVb,nostril ; OS, orbito- 

 sphenoid ; P, parietal ; Pf, pre- 

 frontal ; PI, palatine ; Pm, pre- 

 maxillary ; Po, prootic ; PS, 

 parasphenoid; P<, pterygoid ; Q, 

 quadrate ; S, angulo-splenial ; 

 Sq, squamosal ; St, stapes ; Vo, 

 vomer ; II, VII, X, exits of the 

 optic, facial, and glosso- vagus 

 nerves. 



e.g. Ranidens and Hynohins. A pair of nasalia are generally 

 jiresent, but are absent in Xecturus, Proteus, and Siren. The 

 ] larasphenoid is furnished with teeth in the Plethodontinae and 

 Desmognathinae. 



Separate palatine bones exist in Necturus and Proteus, and in 

 the larva of Amhlystoma, but in the adult form they fuse with 

 the vomers, producing the vomero-palatines characteristic of the 

 majority of Urodela. 



VOL. VIII c 



