GANOCEPHALA. 195 



gosaitrus or primeval lizard, was proposed by Goldfuss to ex- 

 press his conclusion as to the saurian nature of this very old 

 form of reptile. I was led, by a study of nearly the same 

 materials, to view the animal as having been more nearly 

 allied to the peremiibranchiate batrachia ; and additional 

 evidence, while confirming the conclusion of the position 

 of Arcliegosaitrus between fishes and reptiles, has shewn that 

 it links on with those older ganoid forms of the gill-breathing 

 class, rather than with the more modern soft-scaled teleosteal 

 fishes with which the Proteus and Siren are closely allied. 

 I have not been able to discern a distinct vertebral body at 

 any part of the space between the ossified neural or haemal 

 arches : in some specimens the notochord has plainly been 

 persistent in the trunk. 



Coincident with this non-ossified state of the basis of the 

 vertebral bodies of the trunk (fig. 84, c), is the absence of the 

 ossified occipital condyles which characterize the skull in 

 better developed Batrachia. The fore part of the notochord 

 has extended into the basi-sphenoid region, and its capsule 

 has connected it by ligament to the broad flat ossifications 

 of expansions of the same capsule, forming the basi-occipital 

 or basi-sphenoid plate. In fig. 84 are represented the chief 

 modifications of the vertebrae, as shewn in the neck, thorax, 

 abdomen, sacrum, and tail. The vertebrae of the trunk in the 

 fully-developed full-sized animal present the following stage 

 of ossification : — 



The neurapophyses (fig. 65, n) coalesce at top to form 

 the arch, from which was developed a compressed, sub-quad- 

 rate, moderately high spine, with the truncate or slightly 

 convex summit expanded in the fore-and-aft direction so 

 as to touch the contiguous spines in the back ; the spines 

 are distinct in the tail. The sides of the base of the neural 

 arch are thickened and extended outwards into diapophyses, 

 having a convex articular surface for the attachment of the 



