626 MR. G. A. BOULENGER ON THE 



3. Prosymna variabilis Werner, Jahresh. Nat. Ver. Wiirt- 

 temb. Ixv. 1909, p. 57. 



Moschi, German E. Africa. 



18. SCAPHIOPHIS. 



Peters, Mon. Berl. Ac. 1870, p. 644 ; Bouleng. Cat. Sn. ii, 

 p. 254. 



1. ScAPHioPHis ALBOPUNCTATUS Peters, t. c. p. 645, pi. i. fig. 4 ; 

 Bouleng. 1. c. 



Tropical Africa, from the Soudan to the Congo. 



19. Dasypeltis. 

 Wagl. Syst. AmjDh. p. 178 ; Bouleng. Cat. Sn. ii. p. 353. 



1. Dasypeltis scabra. 



Coluber scaher Linn. Mus. Ad. Frid. p. 36, pi. x. fig. 1. 

 Dasypeltis scabra Bouleng. t. c. p. ^^54. 

 Tropical and South Africa, Egypt, S. Arabia. 



B. Opisthoglyplia. 



I. Ej-e moderate or large, with vertically elliptic pupil ; head distinct from neck ; 

 nostril between two shields ; loreal present (sometimes entering the eye). 



A. Nostril directed upwards, between the nasal and the 



internasal ; parietals broken up into small shields ; 



scales smooth or obtusely keeled, in 21 rows Fj/thonodipsas. 



B. Nostril between two nasals ; scales smooth or faintly keeled. 



1. Two superposed anterior temporals : scales oblique. 



Scales in 19 or 21 rows, vertebrals not enlarged TarbopJiis. 



Scales in 21 to 25 rows, vertebrals enlarged Dipsadomorphus. 



2. A single anterior temporal. 



Scales in 19 rows (rarely 17) ; loreal not entering eye Leptodira. 



Scales in 17 rows ; loreal entering ej'e Cliaincetortus. 



II. Eye small, with vertically subelliptic pupil ; head distinct 

 from neck ; nasal semidivided, with horizontal cleft ; 

 scales in 17 or 19 rows Semirhagerrhis. 



III. Eye moderate or large, with round or hoi'izontal pupil ; head distinct from 

 neck ; loreal present. 

 A. Pupil round. 



1. Loreal not more than once and a half as long as deep; scales in 17 or 19 



rows, not oblique. 

 Nostril between two nasals ; ventrals 128-139 ; subcaudals 



34-44 Geodipsas. 



Nostril in a semidivided nasal ; internasals shorter than pra3- 



frontals ; ventrals 147-187 ; subcaudals 59-98 Amplorliiniis. 



Nostril between two nasals and the internasal ; subcaudals less 



than 70 Trimero7'hinus. . 



Nostril between two nasals ; rostral verj' large ; subcaudals 90 



or more SJiampJiiopJiis. 



2. Loreal at least once and a half as long as deep ; scales more or less oblique. 



Scales in 17 rows ; a single anterior temporal Dromoph is. 



Scales in 11 to 17 rows ; one or two middle maxillary teeth 



much enlarged, fang-like Fsammopliis. 



