188 REPTILIA : OPHIDIA. — XXVIII. 
bones of both jaws and of the palato-pterygoid arch freely movable, 
united by ligaments only. Limbs wanting; the shoulder girdle 
wanting ; the pelvic girdle usually so, rarely rudimentary, and with 
the hinder limbs represented by small spurs on the sides of the 
vent; vent a transverse slit; tongue forked, capable of protrusion ; 
no eyelids, nor external ears. Various anatomical characters dis- 
tinguish the snakes, but the elongated form and absence of limbs 
separate them at once from all our other vertebrates, excepting the 
lizard Ophiosaurus, and this is not, in any other respect, snake-like. 
(dgis, snake.) 
Families of Ophidia. 
a, Maxillary horizontal, not excavated; no trace of hinder limbs; no deep 
pit between eye and nostril; poison fangs wanting, or if present, per- 
manently erect. 
6. Upper jaw with solid teeth only; no grooved nor perforated fangs. (Non- 
venomous.) . « . « » » CoLusRips, 110. 
6b. Upper jaw with apermanenty erect perforated fang in front. (Somewhat 
venomous.) . . « « . . Evarips, 111. 
aa. Maxillary vertical ; aspen jaws: in " front with large, erectile perforated 
fangs; fangs not grooved in front; a deep pit on each side behind 
nostri], partly occupying the excavated maxillary. ( Venomous.) 
CROTALID&, 112. 
Famity CX. COLUBRIDAM. (Tue CotvusrinE SNAKES.) 
Both jaws fully provided with teeth, which are conical and not 
grooved; head covered with shields; no poison fangs; no spur-like 
appendages to vent; belly covered with broad band-like plates 
(ventral plates or gastrosteges): tail conical, tapering ; sub-caudal 
plates (urosteges) arranged in pairs. 
A very large family comprising 225 genera, and upwards of 700 
species, found in nearly every part of the world, but most abundant 
in warm regions. They differ from the Elapide in the want of 
erect poison fangs; from the Crotalide, in having both jaws fully 
provided with teeth, and in the absence of erectile poison fangs; and 
from the Boide and their relatives in the want of the spur-like ru- 
dimentary posterior limbs. 
uw. Head conic, not distinct from the body, which is cylindric and rather 
rigid. (Calamariine.) 
b. None of the teeth grooved; scales not keeled; anal plate bifid; inter- 
nasals 2. 
c. Prefrontals 2. 
d. Nasal plate single, pierced by the nostril; lorals present; no pre= 
ocular. 
e. Scales in 13 rows; postorbital single (ventral plates 120 to 135). 
CaRPHOPHIOPS, 269. 
ee. Scales in 19 rows; postorbitals 2 (V. P. 170 to 185). 
AsasTor, 270, 
