17 



Eight upper labials, seventh higher than long; fourth and fifth 

 entering orbit; temporals 1-2; genials subequal ; brown with 

 darker brown spots; below speckled S. gemmistratus Cope. 



As the last; third, fourth and fifth labials in orbit; very pale, 

 with large black, yellow edged dorsal spots extending to 

 belly ; belly white H. tenuissimus Cope. 



aa Anterior border of frontal plate longer than lateral 

 borders. 



Seven superior labials, sixth longer than high; temporals 3-3; 

 genials subequal ; muzzle very short; spots larger; belly with 

 a medium stripe of speckles H. platycephalus Cope. 



The detailed characters of the H. platycephalus are as fol- 

 lows : Scales in seventeen rows, those of the vertebral row much 

 enlarged, truncate; the eighth row smaller than the first. Head 

 very wide; muzzle short, not longer than the diameter of the 

 eye measured along the median scutal suture. Frontal plate 

 one-fourth longer than wide, anterior suture one-third longer 

 than supraocular suture. Superior labials seven; third and 

 fourth bounding orbit, sixth and seventh longer than high. 

 Loral higher than long; oculars 1-2. Temporals 3-3-4. Oc- 

 cipitals a little longer than frontal on median suture, the ex- 

 ternal borders regularly convex. Postgenials equal or exceed- 

 ing pregenials. Body compressed. Gastrosteges 228; urosteges 

 124. Total length, 360 mm. ; tail, 92 mm. 



The ground color is a very pale brown. This is crossed by 

 numerous transverse dark brown, light-edged spots, which are 

 approximated on the median line, and diverge as they narrow 

 downwards. These extend to the gastrosteges except on the pos- 

 terior third of the body, where the separated apices form a series 

 of small lateral spots. Here and there is a small alternating 



Color above light brown, below straw-color. Closely placed brown 

 spots extend to the gastrosteges in front, and have their lateral angles 

 cut off as lateral spots posterior to the middle. The centres of the 

 dorsal spots are paler than their borders. Centres of cephalic plates 

 brown. Inferior surfaces irregularly speckled with brown; no stripes; 

 throat and lips unspotted. 



The very short postgenial plates with the low seventh superior 

 labial, and only four inferior labials joining the pregenials distinguish 

 this species from the H. cenchoa; although the last character is some- 

 times found in that species. Santa Clara, Costa Rica. Sen. Alfaro. 

 Mus. nac. de Costa Rica, No. 92. 



