160 . OPHIDIA. 



eighth are much larger than the rest ; the last is somewhat smaller 

 than the penultimate and the ante-penultimate. The triangular sym- 

 phjseal is entirely inclosed by the first pair'of lower labials, which are 

 narrow and acute posteriorly. There are twelve lower labials, increas- 

 ing in size to the sixth, which is the largest ; they again diminish pos- 

 teriorly, the eleventh and twelfth being the smallest of all. We observe 

 two pairs of mental shields ; the anterior pair is longer and broader 

 than the posterior pair, which is acute, diverging, so as to admit some 

 of the scale-like shields which cover the throat. 



The neck is narrower than the head, and a little more slender than 

 the bod}^, which is subcircular, being a little deeper than wide ; the 

 latter tapers posteriorly, passing into the pointed tail, which constitutes 

 about the fifth of the entire length. The scales are subrhomboid, and 

 disposed upon nineteen longitudinal series, seven of which may yet be 

 observed upon the base of the tail. The abdominal scutellae are trans- 

 versely well-developed, one hundred and seventy-four in number, the 

 preanal being divided. The subcaudal scutellae are disposed upon a 

 double series, fifty-eight in each. 



The head, anterior to the occipital plates, is deep blackish-brown ; 

 the occipital region is dull yellow. The upper surface of the body and 

 tail exhibits a series of black transverse patches, occupying from three 

 to four and sometimes five scales, giving it a semi-annulated appear- 

 ance ; these patches, however, are narrower towards the sides ; some- 

 times they are irregular and interrupted. A whitish-yellow space, of 

 the width of about two scales, widening towards the sides, alternates 

 with these black patches. The inferior region is yellowish-white, duller 

 than on the upper surface, semi-annulated with black, alternating with 

 tlie black patches of the back. The inferior half-rings are often inter- 

 rupted along the mesial line of the abdomen. 



- Log. — From the neighborhood of Rio de Janeiro, Brazil. 



Plate XI, fig. 1, represents LiopTiis merremi, size of life. 



Fig. 2, is a side view of the head. 



Fig. 3, an upper view j 



Fig. 4, an under view of the same region. 



Fig. 5, represents the dorsal scales. 



Fig. 6, the vent and adjoining scutellae. 



Figs. 2-6, are magnified about half their diameter. 



