152 bulletin: museum of comparative zoology. 



Diagnosis. Nasals broadly in contact with the rostral. Prefrontal 

 region covered by a pair of elongate supranasals, broadly in contact 

 with the middle line of the snout, immediately followed by two pairs 

 of prefrontals and a fifth scale wliich is intercalated at the crossing 

 point of the sutures, the posterior pair several times as large as the 

 anterior pair; both pairs of prefrontals broadly in contact in the middle 

 line of the snout. Frontal region covered by a transverse row of four 

 large scales in contact with the prefrontals and by two more large 

 scales mesially arranged and separated from the transverse row by 

 a single row of small scales. Supraorbital semicircles not apparent, 

 but the scales of the supraocular region much smaller than those of 

 the frontoparietal regions. Canthus rostralis consisting of a very 

 elongate can thai scale preceded by a small precanthal ; all these scales 

 on the top of head very slightly swollen, some scarcely keeled. Dorsal 

 crest consisting of very low blunt spines, the largest scarcely three 

 millimeters high, this crest greatly diminished but not interrupted 

 on the shoulders, widely interrupted, however, on the rump, sixty 

 spines from shoulder to rump. Color above grayish brown sprinkled 

 very slightly with yellowish gray; spinal region tinged with straw 

 color; sides of the snout blackish; gular region chalky white in strong 

 contrast to the rest of the ventral surface. 



Habitat. — U. Cay in Allen's Harbor, Highborn Cay, Bahamas. 

 Probably now extinct. 



Description of Type. — Rostral as wide as the mental, broadly in 

 contact with the nasals ; nasal large, somewhat ovoid, perforated by a 

 large ovoid nostril; each nasal in contact with an elongate supra- 

 nasal and a triangular postnasal; nasals barely, supranasals broadly 

 in contact in the middle line of the snout; supranasals immediately 

 followed by two pairs of prefrontals and a fifth scale incalated at the 

 crossing point of the sutures; the posterior pair several times as large 

 as the anterior pair; both pairs of prefrontals broadly in contact in 

 the middle line; no definite supraorbital semicircles; scales of the 

 supraocular region much smaller than those of the frontal region; in 

 contact with the prefrontals a transverse row of 4 large scales; sepa- 

 rated from this row by a single row of small scales two more large scales 

 mesially arranged, occipital located well forward and flanked on 

 either side by a group of scales larger than those of the frontal region; 

 frontal region covered by scales somewhat larger than those of the 

 occipital region; two or three rows of superciliary shields not clearly 

 differentiated; canthal scale very elongated, preceded by a small 

 prefrontal, all these scales of the top of head very slightly swollen, 



