162 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



least as long as distance from mouth to ear-opening ; scales on under side of 

 tail twice as large as those on the upper side, all keeled ; scales on dorsal surface 

 of hands and feet multi-carinate. Adults with a high longitudinal cervico- 

 nuchal flap ; males with enlarged post-anal scales. 



Habitat. — Malpelo Island, Pacific Ocean, off Columbia, South America. 



Typc — JJ. S. National Museum, No 22101; March 5, 1891; collector, 

 Chas. H. Townsend. 



Description. — ^ ad. U. S. Nat. Mus. No. 22101. Head once and two thirds 

 as long as broad, slightly longer than tibia ; frontal and occipital regions deeply 

 concave ; supraorbital ridges high, bony, surrounding the occipital hollow, and 

 nearly joining behind it at the beginning of the cervico-nuchal fold ; anteriorly 

 they divide and continue mesially as frontal ridges which converge on the 

 snout, meeting some distance behind the level of the nostrils, while externally 

 they join the supraciliary ridge, and in company the latter extend to under the 

 nostrils as a strong canthus rostralis, thus forming a deep valley on each side 

 between the canthus and the frontal ridge ; there is also a post-superciliary 

 ridge extending to above the ear-opening, and with a valley between it and 

 the occipital ridge ; scales of supraorbital semicircles very much enlarged, 

 forming high tuberculated bony crests, separated by a single series of very 

 small scales ; scales forming frontal ridges and valleys rather large, irregu- 

 larly hexagonal, concave or convex according to situation ; scales on snout 

 smaller, more irregular, elongate, four in contact with rostral; about seven 

 larger supraocular scales, keeled or tuberculated, separated by one row 

 of granules from semicirculars ; superciliary edge with two very elongated 

 scales anteriorly, granular posteriorly ; occipital scale slightly larger than ear- 

 opening, separated from supraorbital semicircle by one row of scales ; three 

 canthal scales ; loreal region with two deep hollows, the posterior one largest ; 

 loreal rows four; a series of large suboculars, of which the one below the 

 posterior angle of the eye descends to the edge of the lip ; rostral very wide 

 and very low, four times as wide as high, nearly rectangular ; six to seven low 

 supralabials in front of the subocular edging the lip, decreasing in height poste- 

 riorly; ear-opening rather small, oval, vertically oblique; nape and neck with 

 a high, flexible dermal crest or flap on the middle line, almost co-extensive 

 with the poorly developed dewlap underneath ; several dermal folds and 

 wrinkles on sides of neck ; mental shield large, with a deep sulcus behind ; 

 gular scales small, feebly keeled ; body feebly compressed ; dorsal scales 

 slightly larger than those on flanks, a few series along the median line de- 

 cidedly, though not abruptly larger, all more or less distinctly keeled and sur- 

 rounded by one or more minute gramUes ; ventral scales slightly larger than 

 dorsals, rhomboidal, imbricate, keeled, about five to six in the distance between 

 nostrils ; scales on anterior surfaces of limbs larger than ventrals, keeled, those 

 on dorsal surface of hands and feet nmlti-carinate ; adpressed hind limb 

 reaches halfway between eye and nostral ; digital expansions very large, 

 thirty-six transverse lamelliB under ii and iii phalanges of fourth toe ; 

 tail less than twice the length of head and body, cylindrical, without crest or 

 keel ; scales on tail larger than ventrals, straight, in transverse rows, but with 



