1897.] 



MZAUDS OF THE GENUS SCELOPOBTJS. 



483 



forming parallel longitudinal series ; 26 or 27 scales between the 

 interparietal shield and the base of the tail ; 6 or 7 scales 

 correspond to the length of the shielded part of the head. Lateral 

 scales keeled, directed upwards and backwards, graduating into 

 the dorsals and ventrals. Ventral scales smooth, bicuspid. 36 to 

 40 scales round the middle of the body. 



The adpressed hind limb reaches the shoulder or the ear ; tibia 

 a little shorter than the shielded part of the head ; the distance 

 between the base of the fifth toe and the extremity of the fourth 

 equals the distance between the end of the snout or the nostril and 

 the ear. 18 to 21 femoral pores on each side. 



Caudal scales nearly as large as dorsals, strongly mucronate. 

 Males with enlarged postanal scales. 



Yellowish or greyish olive above ; a yellowish, black-edged cross- 

 bar between the eyes ; upper surface of snout sometimes blackish ; 

 a yellowish band on each side from behind the eye to above the 

 axiUa, between which a blackish blotch or bar extends across the 

 scapular region ; some less distinct dark cross-bars may follow^ on 

 the back. Male with the lower surface of the head black-and- 

 white in front, pale blue behind, yellowish green on the sides ; the 

 breast and median line of belly salmon-red ; the belly pale blue 

 near the median line, yellowish green on the sides. Female 

 yellowish white beneath, with some chevron-shaped brown 

 markings, pointing backwards, on the throat. 



Sah. Isthmus of Tehuantepec. 



Bocourt states that the single male specimen examined by him 

 lacks the enlarged postanal scales. Notwithstanding this disagree- 

 ment with the specimens before me, I do not entertain any doubt 

 as to the correctness of their identification, 



4. SCELOPORTTS TAEEOVII. 



Sceloporus jarrovii, Cope, in Wheeler's Eep. Explor. W. 100th 

 Mer. V. p. 569, pi. xxiii. fig. 2 (1875), and Proc. Am. Philos. Soc. 

 xxii. 1885, p. 396. 



Sceloporus yarrovii, Bouleng. Cat. Liz. ii. p. 223 (1885) ; Giinth. 

 Biol. C.-Am., Eept. p. 69 (1890). 



Sceloporus iileuroleins, Giinth. 1. c. p. 74, pi. xxxii. fig. B. 



Head-shields smooth or slightly rugose ; frontal transversely 

 divided, rarely broken up into scales, in contact with the inter- 

 parietal or separated from it by a small agj'gous shield, rarely by 

 the frontoparietals ; interparietal as long as broad or longer than 

 broad, much larger than the parietals, which may be divided ; a 



