188 KKITII.IA : orilllH.V. XXVIII. 



bono? of both jaws and of the palatoptoryiroiil anli freely movable, 

 united by ii^j^anients only. Limbs wantinj^; tliv shoulder ^^irdle 

 wantinj;; the jjelvie girdle usually so, rarely rudimentary, and with 

 the liinder limbs rej)resented by small spurs on the sides of the 

 vent; vent a transverse slit; ton<jjue forked, eapable of protrusion; 

 no eyelids, nor external ears. \'arious anatomieal characters dis- 

 tinjjuish the snakes, but the elonijatfd form and absence of limbs 

 sejiarate them at once from all our other vertebrates, exceptint: the 

 lizard Ophiosaurus, and this is not in any other respect, snake-like. 

 (o<^tf, snake.) 



Families of Ophidia. 



a. Maxillarv horizontal, not excavated; no trace of hinder limbs; no deep 

 pit between ej'e and nostril ; poison fangs wanting, or if present, per- 

 manently erect. 

 b. UppLT j:iw with solid teeth only; no grooved nor perforated fangs. (A'on- 



renomous.) C<<ixi»Kii>.i;, 110. 



bb. Upper jaw with a perinanentl}' erect perforated fang in front. (Somewhat 



ft- nomous.) Klai'ID.K, 111. 



aa. Maxillary vertical; upper jaws in front with large, erectile perforated 

 fangs; fangs not grooved in front; a <li'cp p:t on each side behind 

 nostril, partly occupying the excavated niaxillar\-. ( Vcnnmous.) 



Ckotaliu-k, 112. 



Family CX. COLUBRID^. (The Coluhkixe Snakes.) 



Both jaws fully jirovided with teeth, which are conical and not 

 grooved; head covered with shields; no j)oison fjin^s ; no spur-like 

 appendages to vent; belly covered with broad band-like plates 

 (vi-ntral plates or <:!;astroste!ies) ; tail conical, tapering ; sulxaudal 

 plates (urostejxes) arran;;t'd in pairs. 



A very lar<.xi' family comj>risin;; 225 jrenera, and upwards of 700 

 species, found in nearly every part of the world, but most abundant 

 in warm regions. They differ from the Elojiidrc in the want of 

 erect poison fangs; from the Crotalidce, in having both jaws fully 

 provided with teeth, and in the absence of erectile poi.><on fangs; and 

 from the Boidce and their relatives in the want of the spur-like ru- 

 dimentary posterior limbs. 



a. Head conic, not distinct from the body, which is cylindric and rather 

 rigid. (C<ilamnriin(e.) 

 b. None of the teeth grooved; scales not keeled; anal plate bifid; 



d. Na^nl |)late single, pierced by the nostril; lorals present; no pre- 

 ocular. 

 e. Scales in 1.1 rows; po.storbital single (ventral plates 120 to 1.3.'>). 



C.vRi'iioriiiops, 269. 

 ee. Scales in 19 rows; postorbiUls 2 (V. P. 170 to 185). 



AUASTOK, 270. 



