OPHIDIA. 823 



Tropidonotus schistosus, ScWeg., Ess. Phys. Serp., vol. i, 1837, p. 168 ; vol. ii, p. 319 ; Cantor, Journ. 



As. Soc, Bengal, 1847, vol. xxi, p. 938; Dum. & Bib., Erpet. Genl., vol.vii, 1854, p. 596. 

 Tropidonotus moestus, Cantor, Proc. Zool. Soc, 1839, p. 54. 

 Tropidonotus surgens, Cantor, Proc. Zool. Soc, 1839, p. 54. 

 Atretium scUstosum, Cope, Proc. Acad., Philad., 1861, p. 299; Giinther, Rept. Brit. Ind., 1864, 



p. 373; Steind., Reise Novara, Rept., 1867, p. 67; Anderson, Journ. As. Soc, vol. xl, 1871, 



p. 34; Theobald, Descr. Cat. Rept., Brit. Ind., 1876, p. 179; Ferguson, Rept. Fauna, Ceylon, 



1877, p. 20. 

 Helicops schistosus, Jan, Canestr., Arch. Zool., vol. iii, 1865, p. 245, p. 250; Icon. Genl. Ohp., 



No. xxviii, 1868, pi. ii, fig. 3. 



The head is of moderate size ; snout rather pointed. Body of moderate thick- 

 ness. The anterior frontals are triangular and form a very short suture with the 

 rostral, but in two cases out of three before me, they are excluded from the rostral 

 by a small azygos shield which is also wedged between tliem. The posterior frontals 

 are broader than long, and about the same breadth as the anterior frontals. In one 

 out of two, they are united with a notch behind, corresponding to their line of union. 

 In the two, they are divided into three and four pieces. The vertical is long and 

 constricted in the middle, the posterior half tongue-shaped. Occipitals longer than 

 the vertical, rounded behind, sometimes with a portion separated from their hinder 

 extremities. Loreal sub-quadrangidar, higher than broad. 



One preocular reaching to the upper surface of the head. Three postoculars, 

 the lowest in contact with three labials. Temporals 2 + 3 ; two elongate shields in 

 contact with three postoculars. Nine upper labials, the fourth and fifth orbital. 

 Twenty-three maxillary teeth, increasing in length posteriorly. 



Measurements of three specimens. 



No. 1. Length 30-70 inches; head 0-84; tail 7 ?i inches. 

 „ 2. „ 34-50 „ „ 0-60; „ 6-50 „ 



„ 3. „ 24-75 „ „ 0-62; „ 6-58 „ 



(1) Ventrals 153; sub-caudals 62^ 



(2) „ 144; „ 80 

 (3; „ 154; „ 85 



All have nineteen rows of keeled scales. 



Colour uniform dark olive-brown above ; yellow beneath. 



These Yunnan specimens differ from the generahty of Indian examples in the 

 narrow suture between the anterior frontals and rostral ; in the divided posterior 

 frontals; in the presence of nine upper labials, and in having sHghtly larger 

 preoculars, verticals and occipitals, but these featm-es are not sufficiently important 

 to entitle them to specific rank. 



Specimens were obtained at Muangla and Hotha at elevations of 2,000 and 

 4,500 feet. 



It has been generally supposed that this species is more characteristic of the 

 Indian than of the Indo-Chinese, or Malayan fauna. Its occurrence, therefore, in 

 the foregoing slightly modified condition, in the elevated region of "Western Yunnan, 

 is a fact of considerable interest. 



' Imperfect. 



