IIEPTILES. 297 



adult state. Jjicerta Salamcmdra. The species, the type 

 of the genus, is ovoviviparous, and the sexual impregnation 

 is internal. 



G5. Triton. Eft. Tail compressed in all stages of 

 their growth. Lacerta palustris. 



The males in spring are furnished with a divided mem- 

 branaceous dorsal crest, which disappears after the business 

 of procreation. The species are imperfectly determined. 



Feet only two in number. Toes with claws. 



66. SiEENA. Toes four on each foot. Sirena lacerti- 

 na *. 



That this animal, in its adult state, is destitute of gills, 

 may be safely inferred, by a comparison of the obser- 

 vations on its internal structure, made by Hunter "f, 

 with the excellent account of the structure of the Apneu- 

 mona or Proteus, by Configliachi and Rusconi. The 

 concluding observations of these observers are so remark- 

 ably interesting, that we consider no apology due for insert- 

 ing them in this place, as they are given in the Edinburgh 

 Philosophical Journal, vol. v. p. 104. 



*' Having thus terminated the anatomical description 

 of the Proteus Anguinus, we proceed to examine the 

 two following questions ; first, Whether it be true, as 

 many believe, that this reptile can respire, at the same 

 time, by gills and by lungs ? Secondly, If the Sirena 

 lacertina is to be regarded as a larva or a perfect ani- 

 mal ? To determine these questions, it will be necessary to 

 compare the branchial structure, the organs of circulation, 

 and the supposed lungs of the proteus,with the correspond- 

 ing parts in the sirena and in the larva of the salamander 

 and of frogs. 



• Phil. Trans. 1T66, Tab. ix. p. 189. 

 + Phil. Trans. 1766, Tab. ix- p. 307. 



