SKULL 



101 



separated by wide spaces ; and even where connected sheets 

 of cartilage are present, they are very delicate and thin. At the 

 same time the skull nearly resembles that of Urodeles (more 



Cp 



K, !-. l-l V 



Cp Rad.I 



Fit;. 7-4. HYOIJRANOHIAL APPARATUS OF UKODELKS. A, Axolotl (Sirndon. stage 

 of Amblystoma) ; B, Salamandra macvlosa, ; C, Triton cristatus ; D, Spelerpes 



fuscus. 



Cp, Cps, O.th, basihyobranchial or copula ; G.th, thyroid gland ; Hpbr. I and II, 

 first and second hypobranchial ; HpH, Bad I, hypohyal ; Kebr. I IV, first 

 to fourth ceratobranchial ; Keif, ceratohyal ("anterior cornu " of hyoid in 

 Caducibranchs the "posterior cornu " being made up of Hpbr I and II and 

 Kebr I). Rad. II arises in Salamandra secondarily during metamorphosis. 



especially perennibranchiate forms) in spite of a considerable 

 reduction in its parts especially in the occipital, auditory, and 

 orbital regions, as well as of the peculiar and characteristic 



II* 



