776 



COMPENDIUM OF GENERIC DISTINCTIONS. 



Genuf. IGUANA. Pores on thigh. Throat- pouch larjre 

 and compressed ; toothed in front. Scales of back mode- 

 rate. Tail compressed. Tropical America. 



Genus. ALOPONOTUS. Scales of back very m'rmte. 

 Throat-pouch not toothed. Rest like Iguana. St. Domingo. 



Genitfi. METOPOCEROS. Throat- pouch small, with a cross 

 fold. Middle toes of hind feet toothed. Head-shields flc.t, 

 a large horn-like tubercle on forehead, and two pair of large 

 plates between nostrils. Pores on thigh in two rows. St. 

 Domingo. 



Genus. OREOCEPHALDS. Head-shields conical and deeply 

 wrinkled. Outer toes of hind feet very long. Rest like pre- 

 ceding genus. Galapagos. 



Genus. BASILISCUS. Head long, with crest behind ; a 

 pin-like crest along the back and tail. No pores on thigh. 

 Throat with cross fold. Outer toes of hind feet webbed 

 at base, not fringed at sides. Tropical America. 



Genus. XIPHOSURUS. Throat-pouch large and dilatable. 

 No pores on thigh. Toes dilated under last joint but one. 

 Tail with bony crest Central America (?). 



Genus. ANOLIUS. Back simple, or with little double 

 crest of small scales. Rostral shield erect, nose rounded. 

 Rest like Xiphosurus. North America. 



Genus. PHRYNOSOMA. Body flattened and covered 

 with small scales. Sides toothed. Head armed with spines. 

 Tubercular scales scattered over back and tail. California. 



Family. AGAMIDJB. Teeth on edge of jaws ; tongue 

 short, sometimes without a niche at the tip. Limbs strong, 

 thumb of hind feet on same lino as the toes. 



Genus. DRACO. Body compressed, scales overlapping ; 

 ribs greatly elongated, supporting expansion of skin. Three 

 pouches on i/m-oat Ears not scaled; nostrils below face- 

 ridge. Java. 



Genus. GONYOCEPHALIJS. Ribs simple, back with crest. 

 Five toes on each foot. Tail with long-keeled scales beneath ; 

 ears exposed. Java. 



Genus. CHLAMYDOSAURUS. Pores on thigh. Scales irre- 

 gular and overlapping. Toes fringed ; throat with a fold ; 

 back crested. Neck with a large frill-like expansion on 

 each side. Australia. 



Genus. GRAMMATOPHORA. Back without crest, covered 

 with cross rovs of large scales. Pores of thigh numerous. 

 Neck without frill. Australia. 



Genus. STELLIO. Body flattened, throat with a cross 

 fold, back covered with overlapping scales. Several rows of 

 ventral po.-es. Ears exposed. Tail covered with large spine- 

 like scales in regular rings. Northern Africa and Asia. 



Genus. AOAMA. Single row of ventral pores. Scales 

 keeled. Back not crested or toothed. Northern Africa. 



Genus. MEQALOCHILUS. No ventral pores. Ears hidden. 

 Toes fringed on side. Edge of mouth fringed. Russia. 



Genus. UROMASTYX. No ventral pores, but some on 

 the thighs. Ears exposed. Tail broad and flat, covered 

 with regular rings of spiny scales. Northern Africa and 

 Russia. 



Genus. MOLOCH. No pores. Ears exposed. Neck with 

 a large convex tubercle on its upper surface. Body and 

 limbs covered with 1 arge spiny tubercles. Australia. 



Tribe. DEN BROS A URA. Body compressed. Scales 

 granular and arranged in circular bands. Eyes projecting, 

 globular, covered with circular lid 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, 

 nostrils at sides of muzzle. 



Family. CROTALID2E. 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. LACHESIS. Plates under tail in four rows. 

 America. 



Genus. CENCHRIS. Head shielded. Plates under tail 

 in one row. Tail ending in a spine. 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.2E. 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. 



Genus. 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 somilunar. Keel 

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

 Eyelid of male 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 

 upwards. Europe. 



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

 shields. Europe. 



Genus. ACANTHOPHIS. Head flat and projecting over 

 eyes ; nostrils between two shields. TaU ending in a 

 hooked spine. Australia. 



Sub-order. COLUBRINJ3. Both jaws strong and toothed, 

 with fangs in front or grooved teeth behind. 



Family. HYDRID.ZE. 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 compressed. Pacific. 



Genus. HYDRO PHIS. Head short ; nasal shield four- 

 sided ; rostral shield five-sided and with three teeth below. 

 Tail compressed. Asia. 



Genus. ACROCHORDUS. Head rcaled, 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 bread 

 shields. Tail conical and tapering. 



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

 small scales. Tail scaled beneath. 



