242 



EXPLANATIONS 



changed, and then say if the labyrinthidon nay not be tfe» 

 very first step from some ichthyic form. What thougn 

 the proportions of the head remind Mr. Owen of the 

 sauria, and remove the animal, as he thinks, above the 

 present batrachian type ! Against any such inferences 

 we have the positive fact, in the organization of this 

 batrachian, of a biconcave form of the vertebrae, the form 

 peculiar to fishes, — arguing, by Mr. Owen's own acknowl- 

 edgment, aquatic if not marine habits, — also a decidedly 

 piscine character in the arrangement and even micro- 

 scopic structure of the teeth, together with that position 

 of the breathing apertures near the end of the snout 

 which we see in crocodiles, for the purpose of allowing 

 them to drag their prey under water without ceasing to 

 respire. With regard to the lacertilia, we have this same 

 fish-like biconcave form of the vertebrae, and the same 

 fish-like arrangement of the teeth, equally arguing that 

 alliance to the lower vertebrate class which it is the 

 pleasure of this hardy critic to deny, — the biconcave 

 structure of the reptiles, showing, as Mr. Owen himself 

 owns, that these animals, which the Edinburgh reviewer 

 deems so utterly separated from fish, had probably " a 

 more aquatic, if not marine theatre of life"* than was 

 assigned to their successors. In subsequent and present 

 reptiles, this form is superseded by the ball and socket, 

 or concavo-convex form ; but it is remarkable that, in the 

 embryo state, the frog and crocodile (if not others) ex- 

 hibit the double hollow form still, resembling in this re- 

 spect the mature animal of the secondary rocks. Such 

 is the actual character of reptiles which our critic would 

 set up as high : he has, after this, only to speak of the 

 annelid as above the butterfly, or the proteus as superior 

 to the land salamander, to establish his character as a 

 naturalist. Need I say that these Permian reptiles are, 

 in reality, by these facts degraded to a place in proximity 

 with fishes ? 



So much for the batrachia and lacertilia. When we 

 come to the great saurian line in the Muschelkalk, Lias, 

 Oolite, and Wealden, we have a case which cannot ba 

 disputed, for here the marine character of the earliest ot 

 tlie series, and their intermediateness between fish and 

 true crocodiles, are admitted by all. The first remove 

 * On the Reptilian Fossils of South Africa Geological Trans 

 actions, Feb., 1845. 



