ARRANGEMENT OF THE REPTILES. 105 



the reptiles. But this arrangement has now become 

 altogether obsolete, at least in this country. 



(110.) The only attempts we are aware of, to place 

 the supposed leading divisions of the whole class in a 

 natural series^ with reference to their circular affinities, 

 are those proposed first by Mr. Macleay, and secondly by 

 Mr. Gray.* Mr. Macleay considers the natural series of 

 the five groups to stand thus : — 1 . The chelonians or 

 tortoises ; 2. The emydo-saurians or crocodiles ; 3. The 

 saurians or lizards ; 4. The dipod ophidians^, or two- 

 footed serpents ; and 5. The apod ophidians, or true ser- 

 pents. He considers that " the extremities of this colmnn 

 appear to meet in the Emys longicollis {Chelodlna 

 longicollis Gray) ; and the whole forms a group which 

 may be distinguished from birds by being cold-blooded^ 

 and from the Amphibia by having two auricles to 

 the heart, by undergoing no metamorphosis, and 

 finally, by a different system of generation."t In re- 

 ference to these remarks (for no other intimations of 

 the author's views are given), it may be observed ge- 

 nerally, that the Whole' of those extraordinary fossil 

 reptiles which the discoveries of geologists have brought 

 to light, and which, most unquestionably, belong to 

 this class of animals, are unaccountably omitted. It 

 may, indeed, be urged that there exists no absolute 

 proof that the Ichthyosaurus, for instance, was not a 

 type of the Amphibia ; but its whole aspect, and the 

 general opinion of all naturalists, concur in associating 

 it with reptiles. Mr. Conybeare, indeed, to whose 

 unwearied zeal and critical acumen we owe so much 

 regarding these exterminated monsters, has most ju- 

 diciously placed them in a distinct order, named by 

 him Enaliosauri. We cannot, therefore, in any cir- 

 cular arrangement of reptiles, pass over a group so 

 remarkably characterised, and so important in its ana- 

 logical relations to other animals. Mr. Gray has made 

 two different arrangements of the class Reptilia : the 

 last of these, which he has honoured us so far as to 

 * Hor. Ent. 263. Ann. of Nat. Hist, vol i, p. 276. + Hor. Ent. p. 263. 



