Animals called , by Linnaeus, Amphibia. 23 
Mammalia and Birds, having warm blood ; and the three infe- 
rior ones, viz. Fifties, Infects, and Worms, not being fur- 
nilhed with lungs. 
In his generic characters, Linnjeus has been more fuccefsful 
than in thofe of the clafs ; infomuch that they may, I think, 
be confidered as the beft hitherto given. Whoever will be at 
the pains of comparing Linnaeus’s genera of Amphibia with 
thofe of Gronovius, will find,^ that the generic characters of 
the former, though few in number, are precife. and diftinct ; 
/ 
while thofe of the latter, though more numerous, are vague, 
indiftinCt, and fometimes inaccurate. As a glaring inftance 
of inaccuracy, I need only refer to the Chamseleon, which 
by Gronovius is made a diftinCt genus, of which one of his 
characters is, Pedes unguibus dejlituti\ whereas, in faCt, the 
feet of that animal are furnifhed with very diftinCt, and pretty 
large, claws. 
But though Linnaeus’s genera of Amphibia are, upon 
the whole, well formed, it muft be allowed to be a great im- 
perfection in them, that the venomous ferpents are not fepa- 
rated from the others. 
From fome expreflions of his, in the Preface to the Mufeum 
Regis , and in the Introduction to the Clafs Amphibia, in the 
Syjlema Naturae, itfeems, that he thought it not eafy to diftin- 
guilh them, by any external characters ; and his ideas refpeCting 
the venomous fangs^ themfelves were (as we fhall fee hereafter) 
fo vague and confufed, that it was hardly pollible for him to 
attempt to found a generic diftinCtion upon them *. 
* As a fort of comparative excufe for Linnjeus, it may be obferved, that 
Gronovius (though he made two more genera of Serpents than Linnjeus) did 
not feparate the venomous ones; neither has he diftinguifhed them by a mark (as 
Linn^us has) or by any other means. 
Whether 
