Both sexes with a nuchal crest, composed of triangular lobes; it is continued along the back as a slight serrated ridge, and gradually disappears on the anterior part of the tail.

Trunk slightly compressed; the upper parts arc covered with smallish, keeled scales, intermixed with larger ones, all having their points obliquely directed upwards.

Back with alternate brown or black and grayish or yellowish-white cross bands which ascend obliquely backwards; head above variegated with black; a light, black-edged cross band on the inter-orbital space.

A large female is almost wholly black above, variegated with yellow, all the larger scales being of the latter color.

This species is a native of Sikkim; it attains to a length of 12 inches, the tail taking two-thirds of it.