39. NATRIX—40. THAMNOPHIS 787 
In Lower California, it was first secured by Xantus near 
Cape San Lucas. It appears to be the most abundant snake 
of the country immediately surrounding San Jose del Cabo, 
and has been taken also at Miraflores, Agua Caliente, and 
Santiago, all in the Cape Region. Mr. Belding’s specimens, 
recorded by Yarrow as taken at La Paz, really came from 
the San Jose River (Belding MS.). 
Habits ——This is a true water snake. Individuals had 
eaten pollywogs and small fish (Mugil brasiliensis). 
Genus 40. Thamnophis 
Thamnophis FrrzincEr, Syst. Rept., 1843, p. 26 (type, saurita). 
Eutainia Bairp & Girarp, Cat. N. Amer. Rept., Pt. I, Serp., 1853, 
p- 24 (type, saurita). 
The body is more or less elongate, usually rather slen- 
der, with moderately long, tapering tail, and head distinct 
from neck. The cephalic plates are normal. The nasals 
are not united. One or two (rarely three) preoculars, and 
one to four, usually three, postoculars are present. The 
temporals are normally 1+2, but may be 1+1, 1+3, 1+4, 
2+2, or 2+3. A loreal normally is present, rarely absent. 
The scales are keeled, in 17 to 23 rows. The anal plate nor- 
mally is undivided, but in rare individuals is divided as in 
the genus Natrix. There are no scale pits. The urosteges 
are in two series. The eye is moderate or small, with round 
pupil. 
Fourteen kinds of garter-snakes from Western North 
America now are recognized. Although the several species 
and subspecies may often be distinguished at a glance by 
one familiar with their several characters, the amount of 
individual variation is so great that it is quite impossible to 
make a key which will properly refer all specimens. The 
following synopsis will, I believe, usually serve its purpose, 
bat should not be trusted too implicitly. 
