30 Dr. Gray’s Ohfervations on the Clafs of 
4'thly, That carinated fcales are, in fome meafure, cha- 
rade riftic of venomous Serpents, fince in them they are more 
common than fmooth ones, in the proportion of nearly 4 to 1 ; 
whereas, fmooth fcales are, in thofe Serpents which are not 
venomous, more common, in the proportion of nearly 3 to 1. 
Upon the whole therefore it appears, that though a pretty 
certain conjedure may, in many infiances, be made, from the 
external charaders ; yet, in order to determine, with certainty, 
whether a Serpent be venomous or not, it becomes necefi’ary 
to have recourfe to fome more certain diagnoftic. This can 
only be fought for in the mouth ; I fhall therefore next con- 
iider, how the fangs, with w 7 hich the mouths of venomous 
Serpents are furnifhed, are to be diftinguifhed from common 
teeth. 
To thofe who form their ideas of the fangs of venomous 
Serpents, from thofe of the Rattle-fnake, or even from thofe 
of the Englifh Viper, it will appear ftrange, that there fhould 
be any difficulty in diftinguilhing thofe weapons from common 
teeth ; and indeed the diftindion would really be very eafy, were 
all venomous Serpents furnifhed with fangs as large as thofe of 
the fore-mentioned fpecies. But the fad is, that in many 
fpecies the fangs are full as fmall as common teeth, and con- 
fequently cannot, by their fize, be known from them ; this 
is the cafe with the Coluber laticaudatus *, ladeus, and feveral 
others. I cannot, however, better demonftrate that the dif- 
tindion, between the venomous fangs and common teeth, is not 
very obvious, than by fhewing how very vague and erroneous 
* This fpecies is by Linnaeus reckoned. venomous, in the Mufeum Regis, 
though the mark is not affixed to it in the Syftema Naturae. To me it appears 
to be certainly venomous, and is the only water Serpent I have met with that 
is fo. 
Lin- 
/ 
