XIII CLASSIFICATION — TVPMLOPIDAE 593 



B. Coronoid absent ; squamosal ]>rcsent. 



1. Maxillary horizontal ; ]>tc'iv<:oi(l n.-aeliing quadrate or inandihle. 

 Prefrontal bone in contact wilh nasal. Xcn02)eUidae, p. 605. 

 PivtVontal not in contact witli nasal. Colnhn'dar, p. 606. 



2. !^!axillaI■v horizontal ; jitervgoid not ifncliing quadrate or man- 

 dible. Amblycephalidae, jx 637. 



3. Maxillary vertically erectile, perpendicularly to ectopterygoid ; 

 pterygoid reaching quadrate or mandilile. Viprrirhit', p. 637. 



For ordinaiy practical purpo.ses this synopsis is useless, Ijeing 

 based entirely upon anatomical characters, not all easily ascer- 

 tained. TJie following characterisation of faniilies may therefore 

 be preferred : — 



Eyes A'estigial ; no teeth in tin- lower jaw ; witliout enlarged ventral scales. 



Typhlopidae. 

 Eyes vestigial ; teeth restricted to the lower jaw ; without enlarged ventral 



scales. Glanconiidae. 

 Eyes very small ; head not distinct ; ventral scales scarcely enlarged ; tail 



extremely short, ending obtusely and covered with peculiar scales. 



Uropeltidae. 

 "With vestiges of the hind-limbs appearing as claw-like spurs on each side of 



the vent ; ventral scales transversely enlarged; eyes fumtioual, free. 

 Ventral scales scarcely enlarged. Ilysiidae. 

 Ventral scales transversely enlarged. Boidae. 

 "With a pair of poi.son-fangs in the front part of the mouth, carried by the 



otherwise toothle.-^s, much shortened, and vertically erectile niaxillaries ; 



ventral scales transversely enlarged ; eyes free. I'iperidae. 

 All the remaining Snakes comlnne the following cliaracters : the niaxillaries 



are typical, not separately movable, horizontal, with a series of 



teeth.^ The mandible is toothed but has no coronoid Ijone. 



There are no vestiges of limbs or of their girdles. The eyes are free. 

 Dentary movably attached to the tip of the articular bone of 

 the mandilile ; skin beautifully iridescent. Xenopeltidae. 

 "W^ithout a mental groove ; the ends of the jiterygoids are free, not reaching 



the quadrates. Amhhjcephalidac. 

 "With a median longitudinal groove between the shields of the chin ; the 



squamosal is horizontally elongated, movable ; the pterygoid reaches 



the quadrate. Colubridae. 



Fam. 1. Typhlopidae. — Burrowing snakes which have the 

 \vhole body covered with uniform cycloid scales, and with the 

 teeth restricted to the small and transversely placed maxillary 

 bones. Tlie pterygoids do not extend backwards to the 

 quadrates, and there are no endopterygoids. The quadrates 

 slant obliquely forwards, and are attached directly to tlie pro- 



' Except Oli'jodon, DasijpeUis and Atractaspis (.see p. 582), in whicli jialatal 

 teeth are restricted to tlie palatines. 



VOL. VIII '1 Q 



