1. cAtrsus. 469 



■edge. -Rostral broader than deep, forming nearly a right angle 

 rabove, its upper portion measuring one half to two thirds its distance 

 from the frontal; internasals longer than the prsefrontals, separated 

 from or just touching the loreal ; frontal once and a half as long as 

 broad, as long as or longer than its distance from the end of the 

 snout, longer than the parietals ; two prBeoculars, two postoculars, 

 and one or two suboculars separating the eye from the labials ; 

 temporals 2+3 or 4; six upper labials ; four lower labials in contact 

 ■with the anterior chin-shields ; posterior chin-shields very small or 

 indistinct. Scales smooth or faintly keeled, in 19 to 22 rows. 

 Ventrals 134H52; anal entire; subcaudals 17-25 pairs. Greyish 

 olive above, uniform or with curved or chevron-shaped black cross- 

 'ba.TB pointing backwards ; uniform white beneath. 



Total length 470 millim. ; tail 40. 



Sennar, East and Central Africa, Angola. 



M. $ (Sc. 22 ; V. 146 ; Ngatana, E. Africa. Dr. J. W. Gregory 



0. 18). [P.]. 



J). Yg. (Sc. 22 ; V, 148 ; Mkonumbi, E. Africa. Dr. J. W. Gregory 



0. 23). [P.]. 



4:.-d. S (Sc. 22 ; V. 145 ; Lamu, E. Africa. F. J. Jackson, Esq.^ 



C. ]8) &yg. (Sc. 21; [P.]. I 



V. 146 ; 0. 18). y 



■e. § (Sc. 22 ; V. 144 ; L. Tanganyika. Sir J. Kirk [0.]. I 



C. 19). J 



(Types of C jachsonii.) 



/. Yg. (Sc. 19 ; V. 144 ; Golungo Alto, Dr. Welwitsch [P.]. 



C. 22). Angola. 



8. Causus defllippii. 



Heterodon defllippii, Jan, Arch. Zool. Anat. Phys. ii. 1862, p. 225, 



and Icon. GH. U, pi. iv. fig. 3 (1865). 

 Ctasus (Heterophis) rostratua, Ounth. Ann. Sr Mag. N. S. (3) xii. 



1863, p. 363, and Proc. Zool. Soc. 1864, p. 115, pi. xv. 

 rostratus, Mocg. Le Natur. xiv. 1892, p. 35; Bocage, Herp. 



Angola, p. 147 (1895). 

 defllippii, Mocq. t. c. p. 64. 



Snout obtusely pointed, prominent, more or less turned up at the 

 ■end. Eostral large, T-shaped, with obtuse horizontal edge; its 

 upper portion forming a right or acute angle behind and quite as 

 long as its distance from the frontal : internasals longer than the 

 prsefrontals and forming a suture with the loreal ; frontal once and a 

 balf to once and two thirds as long as broad, as long as its distance 

 from the end of the snout, longer than the parietals ; two prse- 

 oeulars, two postoculars, and one or two suboculars separating the 

 «ye from the labials ; temporals 2+3; six or seven upper labials; 

 three or four lower labials in contact with the very short anterior 

 «hin-shield8 ; posterior chin-shields very small or indistinct. Scales 

 in 17 rows, dorsals feebly keeled. Ventrals 113-125 ; anal entire ; 

 subcaudals 10-18 pairs. Grey or pale brown above, vertebral region 

 darker, with a series of large rhomboidal or V-shaped dark brown 



