LTTOEHTNCHUS DIADEM A. 271 
LYTORHYNCHUS. 
Lytorhynchus, Peters, Mon. Berl. Ak. 1862, p. 272. 
Body elongate, cylindrical ; tail moderate or short ; head scarcely distinct from the 
neck. Eye moderate, pupil slightly vertically elliptic. Rostral large, folded back on 
the upper surface of the head, and at a sharp angle laterally in front of the nasals, 
concave below. Nostril small, lateral, oblique, between two shields ; one or more 
loreals. Body-scales 19, without apical pits, smooth or feebly keeled, in longitudinal 
and oblique series ; ventrals angulate ; anal divided or entire. Maxillary teeth few in 
number, posterior much longer than the anterior ; mandibular teeth subequal. 
Dr. Alcock and Mr. Finn have found the subocular (so-called) poison-gland well 
developed in the two species L. ridgeioayi and L. maynardi. 
Lytorhynchus diadema, Dum. & Bibr. (Plate XXXVII. fig. 3.) 
Lytorhynchus diadema, Blgr. Cat. Snakes B. M. i. 1893, p. 415; Konig, Verh. (S.B.) uat. Verh. 
Bonn, 1892, p. 22; Matschie, S.B. Ges. nat. Fr. Berl. 1893, no. 1, p. 31 ; Olivier, Mem. Soc. 
Zool. France, vii. 1894., p. 119; Anderson, Herpet. Arabia & Egypt, 1896, p. 107; Franea- 
viglia, Bull. Soc. Rom. Stud. Zool. v. 1896, p. 36. 
Heterodon [Lytorhynchus) diadema, Klunzinger, Zeitschr. Ges. Erdk. Berl. xiii. 1878, p. 95. 
1 J . West bank of Suez Canal, between Suez and Ismailia. 
1 juv. Abu Roash. 
1 <£ . Gizeh, margin of desert. 
Head convex from before backwards ; rostral abruptly transversely truncated, 
continued backwards in a line with the nostrils, sides of its lateral angulation free, 
thick, and more or less puckered, lateral margins of the upper portion more convex in 
some than in others, hardly separated from the prefrontals, its upper portion equalling 
the length of the internasals and prefrontals in the mesial line ; internasal suture more 
than half the length of the prefrontal ; prefrontals in contact with the internasals, 
posterior nasals, loreal, upper preocular, supraocular, and frontal ; the latter rather 
short and broad, shield-shaped, its length equalling the distance of its anterior border 
from the tip of the snout ; anterior nasal the larger ; loreal square, larger in some than 
others, generally lying on the second and third labials, and occasionally in contact with 
the fourth as well. One or two preoculars, and occasionally a subocular ; two 
postoculars ; seven or eight upper labials, the fourth, the fifth, or the fourth and fifth 
entering the orbit. Generally three lower labials in contact with the anterior chin- 
shields, rarely four. Scales smooth. Ventrals 160-187 ; anal 1/1 ; subcaudals 36-16. 
