77* 



COMPENDIUM OF GENERIC DISTINCTIONS. 



C,,-HHS. MOLOCH. No pores. Ears exposed. Neck with a 

 large convex tubercle on its upper surface. Body and limbs 

 covered with large spiny tubercles. Australia. 



Tribe. DENDROSA URA . Body compressed. Scales 

 granular and arranged in circular bands. Eyes projecting, 

 globular, covered with circular jid pierced with a very small 

 round hole. Tongue nearly cylindrical, long, extensile, and 

 rather large at the tip. Ears hidden under skin. Toes five on 

 each foot, arranged in two opposing groups. Tail long and 

 prehensile. Only one genus. 



Genus. CHAMELEO. Characters of tribe. Old world. 



Order. OPHIDIA. Body elongated, true feet none. 

 Mouth dilatable, bases of jaws inseparable. Eyelids and 

 external ears wanting. Tongue long, flat, deeply forked, and 

 sheathed in lower jaw. Vertebrae fitting into each other with 

 ball and socket joint, the socket being in front. 



Sub-order. VIPERIN^E. Jaws weak, upper toothless, 

 but having large fangs in front ; lower jaw toothed. Shields of 

 belly broad and band-like. Top of head flat, eyes at side, nos- 

 trils at sides of muzzle. 



Family. CROTALID^E. Face with a large pit on each 

 side, between eye and nostril. 



Genus. CRASPEDOCEPHALUS. Head scaly, a single shield 

 over eyebrow ; shields of hinder part of lips large ; scales 

 lancet-shaped and keeled. Tail ending in a spine. Plates 

 under tail in two rows. America and islands. 



Genus. LACHBSIS. Plates under tail in four. rows. Amer- 

 ica. 



Genus. CENCHRIS. Head shielded. Plates under tail in one 

 row. Tail ending in a spin*. America. 



Genus. CROTALOPHORUS. Head shielded. Plates under 

 tail in one row. Tail ending in a rattle. Nine large shields 

 behind eyes. America. 



Genus. UROPSOPHUS. Head with scales behind ; shields of 

 temples and lips rather large. Tail ending in rattle. America. 



Genus. CROTALUS. Head with scales behind ; shields of 

 temples and lips very small and rather convex. America. 



Family. VIPERID^E. Head without any pit between 

 the eyes and nostrils. 



Genus. DABOIA. Head flat and long, with sharply-keeled 

 scales. Nostrils large. Pupils of eyes round. India. 



Gemts. CLOTHO. Pupil of eye erect and oblong. Head 

 short and broad, the keeled scales ending in a spine. Rest like 

 Daboia. Africa. 



Genus. CERASTES. Nostrils small and semilunar. Keel 

 of scales not reaching to tip. Two rows of plates under tail. 

 Eyelid of mal: horned. Northern Africa. 



Genus. ECHIS. Nostrils very small, between two little 

 scales. Eyelids of male not horned. One row of plates under 

 tail. Africa and India. 



Genus. VIPERA. Head with shields, flat, and high on 

 sides : nostrils in middle of a shield. Nose rather curved up- 

 wards. Europe. 



Gemts. PELIAS. Nose blunt ; front of head with small 

 shields. Europe. 



Genus. ACANTHOPHIS. Head flat and projecting over eyes ; 

 nostrils between two shields. Tail ending in a hooked spine. 

 Australia. 



Sub-order. COLUBRIN^E. Both jaws strong and toothed, 

 with fangs in front or grooved teeth behind. 



Family. HYDRIDE. Ventral shield narrow. Eyes and 

 nostrils above, nostrils with valve. Fangs moderate, and 

 mixed with teeth of jaw. Pupil small and round. 



Section I . Abdomen keeled, and furnished with long, 

 lancet-shaped shields or scales like those of back. Tail mostly 

 compressed. 



Genus. PELAMIS. Head shielded, flat and long, gape wide ; 

 nasal shield very large. Scales square or six-sided. Tail com- 

 pressed. Pacific. 



Genus. HYDROPHIS. Head short ; nasal shield four-sided ; 

 lostral shield five-sided and with three teeth below. Tail 

 compressed. Asia. 



Genus. ACROCHORDUS. Head scaled, eyes surrounded by 

 series of little scales. Body spindle-shaped, with three cuspid 

 scales. Tail conical and tapering. Java. 



Section II. Abdomen rounded beneath, with broad shields. 

 Tail conical and tapering. 



Genus. ERPETON. Scales keeled ; nostrils in a ring of small 

 scales. Tail scaled beneath. 



Genus. CERBERUS. Head shielded, scaled above ; nostrils 

 in centre of shield. Scales of body keeled and grooved. Asia. 



Family. BOID^E. Hinder limbs developed under skin, 

 and protruding in form of a horny spur on each side of the 

 base of the tail. Tail short. 



Section /.Tail strong and prehensile. Muzzle blunt, head 

 distinct. 



Genus. MORELIA. Crown of head with scale-like plates. 

 Deep pits on lip-shields. Pupil of eye elliptical and erect. 

 Plates under tail two-rowed. Australia. 



Genus. PYTHON. Crown of head shielded to behind eyes, 

 rest scaled. Pits on lip-shields. Pupils of eyes linear and 

 erect. Plates under tail two-rowed. India. 



Genus. HORTULIA. Head with irregular scales, shielded 

 in front of forehead and on muzzle. Pits on lip and rostral 

 shields. Plates under tail two-rowed. Africa. 



Genus. EPICRATES. Scales smooth, plates under tail one- 

 rowed. Crown of head scaly. America. 



Genus. XIPHOSOMA. Lip-plates short and all pitted. Rest 

 as in Epicrates. America. 



Genus. BOA. Scales smooth. Lip-shields short, not 

 pitted. Crown of head scaled ; nostrils at sides, between two 

 plates. America. 



Genus. EUNECTES. Crown with irregular shields ; nostrils 

 between three plates. America. 



Genus. CHILABOTHRUS. Crown of head with regular 

 shields ; nostrils between three scales. Jamaica. 



Sectinn II. Tail very short, rarely prehensile. Head short 

 and indistinct. 



Genus. TORTRIX. Seven shields on head. Pupil of eye 

 circular and covered with a plate, transparent in centre. Scales 

 smooth. One row of plates under tail. Spurs very small and 

 sunk in pits. Tropical America. 



Sub-order. COL UBRINM. Abdomen with broad, band- 

 like plates. Spurs none. Both jaws toothed. Tail conical 

 and tapering. 



Se.-tion I. No grooved or perforated fang in front of the 

 jaw. 



Family. C \LAMARIDrE.-Body cylindrical. Head not 

 distinct from neck, gape small, nostrils small. No keels on 

 plates of abdomen. 



Genus. CONOCEPHALUS. Scales above keeled, in seventeen 

 rows. Two rows of plates under tail. Head conical and nar- 

 row. Teeth equal and smooth. America. 



Family. CORONELLIDjE. Belly flat, back broad. 

 Head rather flat, shields of head regular. Front teeth shortest. 



Genus. PSAMMOPHYLAX. Rostral shield not protruding, 

 rounded, and with a long process pointing backwards. South 

 Africa. 



Genus. CORONELLA. Rostral shield moderate; muzzle 

 short, rounded ; and flat above. Last maxillary tooth smooth 

 or grooved, and rather larger than the others. Most parts of 

 world. 



Family. NATRICID^E. Body rather stout. Tail dis- 

 tinct. Head broad and distinct from neck, muzzle rounded. 

 Gape wide. No keels on plates of belly. 



Genus. TROPIDONOTUS. Scales of back keeled. Muzzle 

 rather narrow. Last maxillary tooth longest. Frontal scales 

 narrow. Most parts of world. 



Genus. HETBRODON. Body short and thick, head short 

 and flat ; rostral shield with a sharp ridge above. America 

 and Madagascar. 



Family. COLUBRINjE. Body moderate, tail tapering 

 Shields of head irregular. Scales oval, overlapping, and 

 nearly equal. Two rows of scales under tail. Teeth no 

 grooved. 



Genus. COLUBER. Rostral shield moderate and rounded. 

 Body with rounded back. Teeth equal. Europe, Asia, and 

 North America. 



Genus. CORYPHODON. Teeth of jaws increasing in size 

 behind and smooth. Asia, Africa, and America. 



