1885.1 265 [Cope 



inferior surfaces are similar in every respect to those of the one described 

 above, while those of the sides, tail, and superior surfaces are quite differ- 

 ent. Those of the tail are flat and keeled, and smaller than those of that 

 species, and of equal size. In the scutellation of the back the granular 

 scales are far more numerous, covering almost the whole of the scapular 

 regions and sides of the neck and body. Where the larger scales 

 appear they are round and not arranged in rows, and are separated 

 by granular interspaces as wide as or wider than themselves. On 

 the temporal and lateral gular regions the larger scales are scattered 

 at wide intervals in the granular surface. On the muzzle there are 

 two pairs of scuta behind the nasal plates, which are separated by a 

 granular interval. Behind these, and separated by another interval, is a 

 knob-like median scutum. Between this and the canthus rostralis, but 

 separated from it by a wide granular space, are several scales like the 

 smaller ones in the same position in the G. nigerrima. There are three 

 rows of small prominent scales over the eye, forming a rough surface. A 

 series of larger scuta on the zygomatic arch, as far as below the front of 

 the orbit. Two prominent scuta not in contact on the anterior border of 

 the tympanum. Two large and two small row9 of infralabial plates. 

 Labials f. Symphyseal plate large, angulate behind. A longitudinal 

 median gular fold, which terminates in a pendulous transverse gular fold. 

 The scales on these folds are like those of the belly, and not granular like 

 those of the lateral gular region. Femoral pores 18. Tail compressed. 

 Dorsal crest low, interrupted at the withers and groin. 

 Color, dark brown ; belly, breast, fore limbs and sides of head black. 



Measurements. M. 



Length of head to end of os quadratum 103 



Width of head at front of tympanum 055 



Length of body to vent 290 



" " tail (tip wanting") 370 



" " foreleg 140 



" " humerus (measured behind) 050 



" forearm 057 



" " hind leg 200 



" " femur (measured above) 058 



" tibia 065 



" hind foot 095 



There are three specimens of this species in the National Museum which 

 agree in all essential respects. They are. from the Island of Navassa. In 

 all of them the temporal and pterygoid muscles are enormously developed, 

 forming swollen enlargements unlike anything seen in any other Iguanid. 



According to Dumeril and Bibron there are in the Metopoceri/s cornutus 

 three pairs of scuta on the muzzle. According to the description of these 

 authors this animal also differs from the M. cornutus in having eight supe- 



PROC. AJIER. PHILOS SOC. XXIII. 122. 2h. PRINTED FEBRUARY 5, 1886. 



