HERPETOLOGY OF PORTO RICO. 673 



the nasals; one large keeled canthal scale nearest the orbit, the anterior 

 ones but slightly developed; a well-developed series of strongly keeled 

 suboculars continued backward as a supratympanic series to above the 

 ear; ten supralabials, the suture between the last two under the center 

 of the eye; a series of small scales separating the suboculars and the 

 supralabials; above the angle of the mouth and in front of the lower 

 edge of the ear a large tubercular shield and above it about the middle 

 of the front edge of the ear another shield, convex and almost as large; 

 tympanum elliptical, erect, large; eleven lower labials to the center of 

 the e\ T e; a series of enlarged malar scales, the posterior ones strongly 

 keeled and separated from the lower labials by several rows of small 

 scales; dorsal and ventral scales small, about eleven contained in the 

 vertical diameter of the t} 7 mpanum, rhomboidal, obliquely keeled, the 

 keels pointing toward the median line; from the occiput along the 

 median line of the neck and back a series of enlarged strongly keeled 

 scales forming a low serrated crest, which is much reduced between the 

 shoulders, absolutely interrupted on the rump, and consequently not 

 continuous with the caudal crest; length of the crest scales on the 

 middle of the back three to the vertical diameter of the tympanum, 

 51 in the dorsal crest from shoulder to rump; throat covered with 

 scales similar to the ventrals but smaller; sides and underside of neck 

 with numerous folds, a large median one almost large enough to be 

 called a dewlap, joining posteriorly a strong transverse fold; upper 

 surface of limbs with slightly imbricated, keeled, posteriori} 7 pointed 

 scales, somewhat larger than the dorsals, on the lower arm about seven, 

 on the tibia about four to the vertical diameter of the tympanum; a 

 single series of about eighteen femoral pores; inner side of second toe 

 with one "comb," of third toe with two "combs" (see fig. 125); tail 

 compressed, covered with obliquely keeled scales in vertical rows 

 forming faintly indicated verticils, about four rows of the larger 

 scales to a verticil; tail surmounted by a crest of enlarged, pointed 

 triangular scales forming a strongly serrated edge. 



Dimensions. 



mm. 



Total length 456 



Tip of snout to vent 176 



Vent to tip of tail 280 



Tip of snout to ear 37 



Width of head 28 



Fore limb 70 



Hind limb 125 



Vertical diameter of tympanum 8 



Variation. — I have described purposely a young specimen, partly 

 because it is the best preserved one in our collection, but mostly 

 because the young show the individual scales and shields better than 

 the older ones. In these, from age and excessive wear, and also because 



NAT MUS 1!>U2 43 



