cm 



COMPENDIUM OF GENERIC DISTINCTIONS. 



Venus. Alligator.— Jaws with small longitudinal ridge be- 

 tween eyes. Hind feet fully webbed. .Nostrils separated by 

 division of bony substance. New World. 



Order. AM PHISB/EN1 A.— Body long and cylindrical; covered 

 with squared plates imbedded in the skin, and arranged in mw 

 rows. Limbs either wanting or very feeble. Jaws with teeth. 



Family. AMPHISB.ENID.ffi:. -Teeth on inner side of jaws. 

 Limbs wanting. Body and chest with similar square shields. 

 Fores before vent distinct. 



Genus. Amphisb/Ena.— Head flattened, muzzle round, rostral 

 shield triangular and erect. Two shields of nose large, square, 

 and extending across muzzle. Brazil and West Indies. 



Family. CHEIROTID.E.— Teeth conical, curved backwards, 

 and separate. Limbs two in front and weak, with five nearly 

 equal toes. Pores before vent distinct. 



Section. SQUAMATA, OR SCALED REP- 

 TILES. -Body covered with overlapping scabs. Skull 

 formed of separate bones; bone of ear external and jointed to 

 skull. Tongue free, long, and nicked at the tip. 



Order. SAURA, OR LIZARDS, -Mouth not dilatable, jaws 

 toothed, bones of lower jaw united in front. Limbs four, and 

 mostly distinct; toes clawed. Body long and rounded. Ribs 

 distinct, and moveable. Tail long and tapering. Eggs 

 covered with a hard skin. 



Sub-Order. LEPTOGLOSS.E. — Tongue flat, long, and 

 forked at tip. 



Tribe. CYCLOSAUIiA.—Scsdes of hack and tail rounded, or 

 granular; those of abdomen squared and set in cross hands. Eyes 

 with two valvular lids. Feet strong, toes compressed. 



Family. MONITORID.ffi. — Head with little, flat, many-sided 

 fc'nehls. Tongue sheathe. 1 at base. 



Genus. Eeoknu. — Tail compressed, with keel of double row 

 of scales. Nostrils large, oblique, and near the eyes. Toes 

 short. Africa, 



Genus. Monitor.— Tail as above Nostrils round, nearly 

 half way between eyes and muzzle. Africa, Asia, and Aus- 

 tralia. 



Fumilii. TEIDJE.-Head with large, regular, many-sided 

 shields; teeth solid; tongue flat and long, mostly free. Scales 

 of back granular or keeled, and rhombic in shape. Sides flat. 

 Throat scaly, with double collar. All the Teidse inhabit the 

 Western world. 



Genus. Tkiuk. — Throat with large hexagonal scales between 

 folds of throat. Ventral shields small, long, and smooth. Five 

 toes on ea.di foot. Pores of thigh distinct. Brazil. 



Genus. Amkiva. — Teeth with three lobes, and compressed. 

 Ventral shield broad and .smooth. Tongue sheathed at base. 

 Brazils and West Indies. 



Genus. Cnemidophorub. — Tongue not sheathe, 1 at base. 

 Teeth compressed longitudinally. Toes liv i each foot. 



Genus. Centropyx.— Throat with collar of large shields. 

 d'ail round. Scales of back large, those of sides gradular. 

 America. 



Genus. An.— Collar and ventral shields smooth and long. 

 Tail compressed. Scales of hack unequal; throat with two 



folds. 



Family. LACERTINIDJE.-- Head pyramidal, with regular 

 many-sided shields. Throat scaly. Tongue long, flat, and 

 deeply forked. Teeth hollow. Scales of body keeled and 

 rhombic, tho f sides small and granular. Shies flattened. 



'""" - '/■■> 'A, -Nostrils erect in nasal shield. Toes sim- 



ple and compressed. Collar distinct. Lower eyelid scaly and 

 opaque. Europe, Africa, and Australia. 



Genus. Lacerta. — Lower eyelid opaque. Chin fold dis- 

 tinct. Shields of abdomen narrow behind. Europe, Africa, 



Asia. 



Genus. ACAXTHOUACTTLUS.— Toes keeled beneath, and fringed 

 on the sides. Palate without teeth. Africa. 



Genus. Erkmias. — Nostril horizontal, between three scales 

 Eyelid distinct. Toes compressed, keeled beneath, not toothed 

 on edge. .Many ventral shields, in several series. Africa. 



Genus. Ophiops. — Eyelid rudimentary, eye circular and ex. 

 posed. Palate not toothed. Pores on thighs distinct. Shores ot 

 the Mediterranean. 



Family. ZONITRIDJE. — Head pyramidal or flattened, with 

 regular many-sided shields. Tongue flat and niched at tip. 

 Scales of back and tail large and rhombic. A fold along the 

 sides. Eyes with two lids. 



Genus. Zonurus.— Head flat. Scales of back and sides 

 square and keeled. Low cr eyelid opaque. Tail spined. P., res 

 of thigh distinct and numerous. Africa. 



Genus. Pseudocordtlus. — Head flat. Scales of back nearly 

 oval, surrounded with granules. Tail spined. Africa. 



Genus. Gerrhosaurus. — Head pyramidal and squared. 

 Tongue scaly. Five toes on each foot. Body spindle-shaped. 

 Tail not spined. Africa. 



'on, is-. Sadrophis. — Toes four on each font, and very short. 

 Body .and tail very long. Tail not spined. Africa ; perhaps 

 Australia. 



Genus. Tachtjdromus. — Head pyramidal and long. Collar 

 of kcehd scales. Ventral scales keeled. Tail not spined. Asia. 



Genus. Pseddopus. — Fore pair of limbs wanting, hinder pair 

 very small and undivided. Body snake-like. No pores on 

 thigh. Africa, parts of Europe, and Asia. 



Genus. Ophisaurus. — Limbs wholly wanting. Two deep 

 grooves along body. Palate toothed. North America. 



Family. CHALCIDJE. — Head with regular many-sided shields. 

 Tongue scaly, palate without teeth. Limbs four, but very 

 small and feeble. No pores on thigh. Body long and cylin- 

 drical. 



Genus. ChaLCIS. — Hinder feet not divided. Scales square. 

 America. 



Family. ANADIADJE.- Lower eyelid transparent. Scales of 

 hack and sides six-sided, not overlapping; those of abdomen 

 four-sided, and arranged in longitudinal sines. Sides rounded. 

 Limbs four, five toes on each foot; numerous pores on thifk. 



Genus. Akadias. — Same characteristics. America. 



Family. CHEIROCOLIDiE. — Lower eyelid transparent. 

 Tongue scaly. Collar double. Ears under skin. Body and 

 tail long and nearly cylindrical. Scales of hack, sides, and 

 tail long, sharp, overlapping, and keeled, arranged in alternat- 

 ing rings. Legs four, and short: pores numerous; toes five on 

 each foot, hinder toes very long. 



Genus. HeterodaCTTLDS. -Same characteristics. America. 



Family. CERCOSAURIDiE. -Upper eyelids very short. Ears 

 distinct. Sides rounded with scales like those of hack. Large 

 keeled scales in series along hack and upper part of tail. Un- 

 der parts with flat squared scales. Limbs four, toes five on 

 each foot, tail round. 



Genus. Cercosaura. — Body long; scales of back oblong, 

 with blunt keels. No pores on thighs. America. 



Family. CHAM.ESAURIDiE. -Palate without teeth. Lowci 

 eyelid scaly. Body ami tail long, and covered with regulai 

 rings of keeled scales. Limbs rudimentary. Ears distinct and 

 small. Sides without groove, and scaled like back. 



