Anal scale
Encyclopedia
Cloaca
In zoological anatomy, a cloaca is the posterior opening that serves as the only such opening for the intestinal, reproductive, and urinary tracts of certain animal species...
l opening. This scale can be either single ("anal entire") or paired ("anal divided"). When paired, the division is oblique. It is preceded by the ventral scales
Ventral scales
In snakes, the ventral scales are the enlarged and transversely elongated scales that extend down the underside of the body from the neck to the anal scale. When counting them, the first is the anteriormost ventral scale that contacts the paraventral row of dorsal scales on either side...
and followed by the subcaudal scales
Subcaudal scales
In snakes, the subcaudal scales are the enlarged plates on the underside of the tail. These scales may be either single or divided and are preceded by the anal scale....
.