RABDION OCCIPITALE. 121 



quadrangular in shape when viewed from above ; they extend to the 

 sides of the head, occupying the place of the loral plate : the latter 

 being absent. The prefrontals are small and subtrapezoid. The rostral 

 is broad, but low and scarcely visible upon an upper view of the head. 

 There is but one subtriangular nasal plate, in the middle of which may 

 be seen a quite large nostril, situated altogether on the sides of the 

 snout. We notice a single anteorbital, of moderate development, 

 extending somewhat to the upper surflice of the head. The supraocu- 

 lary is twice as long as broad. There are two postorbitals ; the 

 uppermost being more quadrangular than the lower, and both a little 

 smaller than the anteorbital. The eyes are proportionally large, and 

 the pupil is circular. The temporal shields are larger than the scales 

 of the body. There are six upper labial plates ; the anterior one is 

 very small, situated under the nasal; the others are well developed: 

 the second is contiguous to the lateral expansion of the postfrontals 

 upon the loral region ; the third and fourth enter into the orbit, the 

 anteorbital resting upon the third, and the inferior postorbital upon 

 the fourth, the commissure of these plates being situated in advance 

 of the pupil ; the fifth and sixth labials are subtriangular, contiguous 

 only upon one of their angles, since the largest of the temporal shields 

 thrusts itself between them. The symphyseal plate is well developed 

 and triangular. We observe seven inferior labials (on each side), the 

 fourth being a great deal larger than the rest. There are two pairs 

 of well-marked mental shields. The region of the throat is occupied 

 by subangular scales, a little larger than those of the body. 



The body and neck are subcylindrical, rather flattened beneath ; 

 the neck is more slender than the body, properly so called. The 

 scales are disposed upon fifteen longitudinal series, smallest along the 

 dorsal line, and increasing in size towards the abdomen. The 

 abdominal scutellae are very narrow, but transversely quite long ; 

 they number about one hundred and eighty, the preanal one being 

 much broader than the others, convex exteriorly, and subdivided. 

 The tail, a little more than an inch in length, is conical and tapering. 

 The subcaudal scutellae are in pairs, thirty-seven in number. The 

 apex of the tail terminates in a horny process. 



The upper surface of the head and anterior portion of the neck is 

 jet black, with an insulated, yellow, occipital spot, transversely elon- 

 gated, convex posteriorly, subconcave anteriorly, and truncated late- 

 rally. The margin of the upper jaw is straw-colored, as is also the 



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