2 $ Dr. Gray’s Qbfervations on the Clafs of 
genera ; and find that eighty of them have fmooth fcales, and 
thirty-two only have carinated ones. Of venomous Serpents I 
have examined twenty-fix ; of which number, twenty have 
carinated fcales, and only fix have fmooth ones.- Upon the 
whole, therefore, carinated fcales muft be confidered as being, 
in feme meafure, a character of venomous Serpents. 
In what I have hitherto faid, I have confidered only the 
three firft genera of Serpents ; I ihall now make fome remarks 
■upon the three laft. 
Thefe th ree (viz. Anguis, Amphifouena, and Caecilia), be* 
fides the charafters affigned them by Linnjeus, have fome 
others which are common to all, and which render them verjr 
different, in their external appearance, from any of the three 
firft genera* Thefe are, a very thick and obtufe tail, and a 
head which is very indiftindt and furnifhed with very fmall 
eyes. This laft character (yh. very fmall ^yes) is fometimes, 
though very rarely, met with among the Colubri, for inftance, 
in the lemnifeatus ; in the three laft genera, however, it takes 
place, I believe, without exception. The thicknefs of the tail is 
alfo common to every fpecies ; and though in the Anguis bipes, 
and in another fpecies, not deferibed by Limnjeus, but figured 
in Browne’s Hiftory of Jamaica (Tab. XLIV. fig. i. f), the 
tail has an acut£ termination, yet in both thofe fpecies, efpe* 
cially in the laft, it continues thick to the end, and becomes 
fuddenly (harp, being what in botanical language would be 
called, obtufa cum acumine . With refpedt to the proportionate 
length of tail, however, it is very remarkable, that the genus 
* This indiftindtnefs of the head, which is more or lefs commorr to each 
genus, is in the Amphilbama fo confiderable, as to have given rife to the fuppofi- 
tion of that Serpent’s having a head at each end. 
f This figure is, by LinnjSUs, erroneoufly quoted as- his Anguis turn- 
toealis*. 
Anguis, 
