8o 



STEGOCEPHALI 



CHAP. 



articulars, angulars, and splenials. The dentaries and apparently 

 sometimes the splenials, the palatines, maxillae, and vomers carry 

 teeth. The eyes possess a ring of sclerotic bones. 



Order I. STEGOCEPHALI LEPOSPONDYLI. 



Vertebrae pseudocentrous. 



Sub-Order 1. Branchiosauri. — The young had several pairs 

 of gill-arches, whicli, tu jiul^e from their size and from the 



L.O S.0 ?P 



Fi(i. 12. — A, Dorsal and B, ventral views of the cranium of Hiandiiosaurus salamun- 

 droides, x about 4. (After Fritscli.) C, Posterior view of the cranium of r/-c«i«<o- 

 sauriis, X about I. (After Fraas.) llr, liranchial arches ; C, condyle ; Ep, epiotic ; 

 /•', frontal ; ./, jugal ; L.O, lateral occipital ; J/, niaxillaiy : A', nasal ; No, nostril; 

 Pa, parietal ; PI, palatine ; Pm, preniaxillary ; I'.n, postorbital ; I'r.f, prefrontal ; 

 /'«, parasphenoid ; /'/.pterygoid; /'(/', ])ostfrontal ; V, (piadrate; V/i <P'''^'l''=d()-jngal ; 

 S.o, .supraoccipital ; Sq, squamosal ; St, supratemporal ; V, vonie:-. 



fact that they are beset with numerous nodules, denticles, or 

 irregular little processes like gill-rakers — seem to have been 

 exposed to the surface and to have carried gills. In the adult 

 the arches and gills seem to be absent. 



One of the commonest genera is Brancliiosaurus, including 

 Frotritoii. B. scdamandroides of the Lower E,ed Sandstone of. 

 Europe is known in every stage, from larvae of 16 mm. to the 

 full grown animal of 64 mm. in lengtli. The whole body was 



