In snakes, the subcaudal scales are the enlarged plates on the underside of the tail.[1] These scales may be either single or divided (paired) and are preceded by the anal scale.
^Wright AH, Wright AA (1957). Handbook of Snakes of the United States and Canada. Comstock Publishing Associates, a Division of Cornell University Press. (7th printing, 1985). 1,105 pp. (in two volumes). ISBN0-8014-0463-0.