320 Miscellaneous. 



c 



dosteus, Sturio, and other Salamandroid ganoid fishes, with well- 

 developed hing-like air-bladders, and of the same skull-bones in 

 the J rchegosaitrus and the Labijrinthodoi^ts : — the persistence of the 

 notochord (^chorda dorsalis) in Archegosaurus as in Sturio : — the 

 persistence of the notochord and branchial arches in Archegosaurus 

 as in Lepidosiren : — the absence of occipital condyle or condyles in 

 Archegosaurus as in Lepidosiren : — the presence of labyrinthic teeth 

 in Archegosaurus as in Lepidosteus and Lahyrinthodon : — the large 

 median and lateral throat-plates in Archegosaui-us as in Megalichthys 

 and in the modern Arapaima and Lepidosteus : — all these characters 

 point to one great natural group, peculiar for the extensive gradations 

 of development, linking and blending together fishes and reptiles, 

 within the limits of such group. The Salamandroid (or so-called 

 ' Sauroid ') Ganoids — Lepidosteus and Pohjpterus — are the most pis- 

 cine, the true Labyrinthodonts are the most reptilian, of the group. 

 The Lepidosiren and Archegosaurus are intermediate gradations, one 

 having more of the piscine, the other more of the reptilian, characters. 

 The Archegosaurus conducts the march of development from the fish- 

 proper to the Labyrinthodont type : the Lepidosiren conducts it to 

 the perennibranchiate batrachian type. Both illustrate the artificiality 

 of the supposed class-distinction between fishes and reptiles, and the 

 naturality of the Hsemacrymes, as the one sole and truly definite 

 group of cold-blooded Vertebrata. There is nothing in the knovra 

 structure of Archegosaurus or Mastodonsaurus that truly indicates a 

 belonging to the Saurian or Crocodilian order of reptiles. The exterior 

 ossifications of the skull and the canine-shaped labyrinthic teeth are 

 both examples of the Salamandroid modification of the ganoid type 

 of fishes. 



The small proportion of the fore-limb of the Mystriosaurus in no- 

 wise illustrates this alleged saurian affinity ; for though it be as short 

 as in Archegosaurus, it is as perfectly constructed as in the Crocodile, 

 whereas the short fore-limb of Archegosaurus is constructed after the 

 simple type of that of the Proteus and Siren. But the futility of 

 this argument of the sauroid affinities is made manifest by the pro- 

 portions of the hind-limb of Archegosaurus. As in Proteus and 

 Amphiuma, it is as stunted as the fore-limb ; whereas in Mystrio- 

 saurus, as in other Teleosaurians, the hind-limbs are relatively larger 

 and stronger than in the existing Crocodiles. M. v. Meyer leaves 

 the hind-limb out of sight in his advocacy of the saurian nature of 

 the so-called Archegosaurus. I regret that v. Meyer's original name 

 * Apateon,' though proposed to express his scepticism of the alleged 

 nature of the fossil submitted to him in 1844 by Dr. Gergens, was 

 not retained by Prof. Goldfuss. It is still more to be regretted that 

 a compound name should in any case be adopted or constructed, 

 where the proof of the affinity it may be meant to indicate is not 

 perfect. Archegosaurus, like Mastodonsaurus, will, I trust, become 

 at length mere arbitrary terms ; but until then, they will really recall 

 or express little more than the mistaken views of the inventors of 

 those names in respect of the true affinities of the remarkable extinct 

 piscine reptiles to which they have been applied." 



