944 



REPORT OF NATIONAL MUSEUM, 1898. 



CHIONACTIS VARIANS Jan. 



CMonactis varians CoPK,FTOc.n.S. Nat. Mus., IX, 1886, p. 189; Bull. U. S. Nat. 



Mus., No. 32, 1887, p. 82. 

 Oxyrhina rarians Jan, Arch. Zool. Phys., II, 1862, p. 60. 

 Conopsis varians Bocoirt, Miss. Sci. Mex., Rept., p. 566, pi. xxxv, fig. .5. — Duofes, 



La Naturaleza (2), 1888, p. 123. 

 Conopsis nasus Gunther, part, Biolog. Centr.-Aiuer., 1893, p. 97, pi. xxxiv, fig. B. 



Head slightly wider than neck. Rostral plate prominent, anguiate 

 in ])rofile, rounded from above, superior surface with a small concavity, 

 and equal to two thirds the length of the distance to the frontal plate. 

 Occipitals longer than frontal, lateral borders concave posteriorly, and 

 emarginate at the point of junction behind. Kostril pierced anterior 

 to middle of nasal plate, which is truncate posteriorly and in contact 

 with the subquadrate loreal. Oculars 1-2; temporals 1-2; three tem- 

 porals bounding the occipitals larger than nuchal scales. Superior 

 labials seven, all higher than long. Pregeneials rather elongate, bor- 

 dered by four inferior labials, of which the fourth is the largest of the 

 series. Postgeneials very small, separated by a scale. Gastrosteges 

 one hundred and thirty-six; urosteges, thirty. 



Measurements. — Total length, 272 mm. ; length of tail, 39 mm. ; length 

 to canthus oris (axial), 10 mm. 



Ground color above brown, with small spots longitudinally arranged; 

 below yellowish unspotted. In the specimen in the national collection 

 there is a series of small, brown, light-edged spots on the middle dor- 

 sal line, which cover the halves or wholes of two scales both trans- 

 versely and longitudinally. On each side of these is a more indistinct 

 smaller dark-brown spot which may be confluent with them ; and fur- 

 ther laterally there are traces of another series of spots. The brown 

 ground color is produced by a dense speckling or reticulation of deep 

 brown on a lighter ground, and these fine markings cover the cephalic 

 scutes, and extend to the extremities of the gastrosteges. According to 

 Bocourt there are sometimes three very indistinct longitudinal stripes? 



This species is well distinguished from the other members of the 

 genus by the form of its occipital plates, and by the longer pregeneials. 

 The same characters distinguish it from the Conopsis nasus. The color- 

 ation is also characteristic. The form of the occipital shields is only 

 partially displayed in Bocourt's figure, as cited, and none of my speci- 

 mens of the C. nasus have even the small posterior emargination shown 

 in Bocourt's figure of that species. In the regular rotundity of the out- 

 line of the occipitals the Conopsis nasus agrees with the species of 

 Chionactis excepting C. varians. 



Chionactis varians Jan. 



Dr. Duges enumerates this species as found in the Valley of Mexico 

 and Guanajuato. 



