55. L1T0EHYNCHTJS. 415 



II, Eostral shield separating the internasals ; one pair of chin- 

 shields ; no labial entering the ej-e. 



Scales smooth 4. decurtatus, p. 417. 



Scales keeled 5. brownii, p. 417. 



1. Lytorhynchus diadema. 



Heterodon diadema, Dam. Sf Bibr. vii. p. 779 (1854) ; Oervais, M^m. 



Ac. Montpellier, iii. 1857, p. 511, pi. v. fig. 1. 

 Simotes diadema, Giinth. Cat. p. 2o (1858) ; Strauch, Erp. Alg. 



p. 53 (1863) ; Boettg. Ber. Senck. Oes. 1878-9, p. 6]; 

 Lytorhynchus diadema, Peters, Mon. Be.rl. Ac. 1862, p. 272, pi. — . 



fig. 1 ; Bouleng. Tr. Zool. Soc. xiii. 1891, p. 145. 

 Chatachlein diadema, Jun, Arch. Zool. Anat. Phys. ii. 1868, p. 228, 



and Icon. Gin. 10, pi. vi. fig. 2 (1865). 

 Catachlasna diadema, Blanf. Proc. Zool. Soc. 1881, p. 678, fig. 



Snout moderately long ; rostral angularly bent, with straight 

 horizontal edge, detached on the sides, the portion visible from 

 above as long as its distance from the frontal ; no lateral cleft in 

 the rostral ; suture between the internasals much shorter than that 

 between the praefrontals ; frontal nearly as long as its distance from 

 the end of the snout, slightly shorter than the parietals ; a small, 

 squarish loreal ; one or two prseoculars, with or without a subooular 

 below ; two postooulars ; temporals l + '2 or 2 + 3 ; seven or 

 eight unper labials, fourth, fifth, or fourth and fifth, entering the 

 eye ; three lower labials in contact with the anterior chin-shields ; 

 posterior chin-shields as long as or a little longer than the anterior, 

 and separated from each other by two series of scales. Scales smooth, 

 in 19 rows. Ventrals 160-188 ; anal divided ; subcaudals 36-46. 

 Pale buff or cream colour above, with a series of large transversely 

 rhomboidal dark spots ; a dark median band along the head and 

 nape, sometimes confluent with an interocular transverse band ; an 

 oblique dark band from the eye to the angle of the mouth ; lower 

 parts uniform white. 



Total length 450 millim. ; tail 60. 



Algerian and Tunisian Sahara, Egypt, Nubia, Arabia, Syria, 

 Persia. 



a. S (V. 162 ; 0. 44). Algeria. 



b. cS (V. 165 ; C. 40). Pvramids of Gizeh. Dr. J. Anderson [P."]. 



c. Yg. (V. 164 ; 0. 42). Abou-Roash, W. of Dr. J. Anderson [P.]. 



Cairo. 



d. ? (V. 182 ; 0. 43). Muscat, Arabia. A. S. Gr. Jayakar, Esq. 



e. 5 (V. 188 ; C. 38). Bushi, S. Persia. 



2. Lytorhynchus ridgewayi. 



Lytorhynchus ridgewayi, Bouleng. Ann. Sr Mag. N. H. (5) xx. 1887, 

 p. 413; Boettg.' Zool. Jahrb. iii. 1888, p. 924; Bouleng. Tr. Linn. 

 Soc. (2) V. 1889, p. 102, pi. xi. fig. 1. 



