CROCODILIANS, LIZARDS, AND SNAKES. 505 



postgenial precedes three pairs of submaxillary ])lates, first pair of 

 Avhicli are in contact along their internal sides, 



Tiie trunk is depressed, of medium length, covered with scales, 

 which form thirty-four longitudinal series; the median dorsal series is 

 composed of seventy-seven scutella, counting from the nape of the 

 neck to the posterior level of the thighs. Scales on the under surface 

 of the body smooth, but those on the back and sides are striated, hav- 

 ing sixteen strife. Preanals are i)olygonal, not exceeding in size the 

 ones which ])recede them. Scales of the normal region of the tail sim- 

 ilar to those on the body; those on reproduced portions are distinctly 

 keeled, forming by contact long prominent lines. Limbs relatively well 

 develoi)ed; length of arm to the end of the middle finger more than 

 one-third longer than the head. Toes of unequal length, the fifth of 

 each foot being the longest. 



MeafiurcmcntH. — Total length, 204 mm.; length of body fi'om chin to 

 anus, 112 mm.; length of tail, 92 mm.; length of head from the end of 

 the muzzle to the posterior border of the occipital, IC mm.; length of 

 head from the end of the muzzle to the anterior border of the ear, 17 

 mm. ; length of head to the level of the temples, 13 mm. ; length of arm 

 to the extremity of the middle finger, 23 mm.; length of leg to the 

 extremity of the longest toe, 30 mm. 



General tint olive yellow; three wide, longitudinal, brown bands 

 extend along the back and sides, the middle one, beginning at the 

 muzzle to the anterior part of the tail, is distinguished from the two 

 lateral by narrow lines of golden yellow, or, in young specimens, blue; 

 its width comprises nine series of scales, each of which has the central 

 longitiulinal line. The lateral bands are thickly strewn on the neck 

 and Hanks with small yellow circular spots rimmed with dark violet, the 

 elVect being that of a black and yellow trellis. The dorsal scales have 

 their borders brown. The cheeks and lower surfaces of the body are 

 briglit yellow, exccjjt tlie throat, which is of a pale tint of the same color. 



Six specimens of this species are before me, all from the Orizaban 

 district of the Toltecan subregion, except one from Costa Rica. (See 

 chapter on geographical distribution.) All have two i)reloreals, one 

 above the other, except one. In one of the former the supraloreal 

 extends down to the superior labial plates between the pre-and post- 

 loreals on one side only, an evident anomaly. In the specimen with but 

 one i)reloreal I proposed the species C. chalyha'us. This specimen has 

 apparently fewer longitudinal rows of scales than the others, but I find 

 that the apparent number of scales depends on the locality in which 

 they are counted. Thus the type of D. cJudyhaus has thirty-four rows 

 on the posterior part of the body and forty on the anterior jiart. Other 

 specimens display the same character. This explains the discrepancies 

 in the figures given by authors. This species was first described from 

 a young example from Jalapa in the museum of the Philadelphia 

 Academy. Specimens in the museums of Loudon and Paris are from 

 the plateau of Guatemala. 



