300 ANNIELLID#,—HELODERMATID &. 
six) round the middle of the body, No enlarged anal scales. Tail 
ending obtusely, when intact measuring one third (or two fifths) 
of the total length. Silvery, the scales edged with brown; a 
narrow brown vertebral line. 
From snout to vent 130 millim ; tail 60. 
California. 
a, Ad. California. Sir J. Richardson [P.}. (Type.) 
2. Anniella nigra. 
Anniella nigra, Fischer, Abh. nat. Ver. Hamb. ix. 1885, p. —.* 
Twenty-eight scales round the body. The three median anal 
scales twice as long as those preceding. Black above, yellowish- 
white inferiorly. Otherwise as in A. pulchra. 
San Diego. 
Fam. 11. HELODERMATIDA. 
Thecoglosse pleurodontes, part., Wagler, Syst. Amph, 1880. 
Trachydermi, TViegmann, Herp, Mex. 1835. 
Varaniens, part., Duméril § Bibron, Erp. Gén. iii. 1836. 
Helodermidee, Gray, Proc. Zool. Soc. 1857, and Cat. Liz. 1845. 
Helodermide, Cope, Proc. Ac. Philad. 1864 & 1866, 
Trachydermi glyphodonta, Bocourt, Miss. Sc. Mex., Rept. 1878. 
Helodermatide, Boulenger, Ann. § Mag. N. H. (5) xiy. 1884. 
Tongue villose, the anterior portion smooth, bifid, protractile. 
Dentition resembling that of the Ophidia, the teeth being fang-like, 
with slightly swollen base, rather loosely attached to the inner edge 
of the jaws; the teeth grooved in front and behind (Heloderma) ; 
teeth on the pterygoid and palatine bones. Premaxillary single ; 
nasals and frontals double; pree- and postfrontals in contact, sepa- 
rating the frontal from the orbit; a strong postorbital arch; uo 
postfrontosquamosal arch ; parictal single ; pterygoids and palatines 
widely separated; infraorbital fossa bounded by the pterygoid, 
palatine, transverse bone, and maxillary. Head with bony tubercles. 
Eyelids well developed. Limbs well developed; clavicle slender ; 
interclayicle without transverse processes ; sternum divided longi- 
tudinally. Skin of upper surfaces tubercular, some of the larger 
tubercles ossifying in the adult, of lower surfaces forming transverse 
series of squarish plates. No femoral or preanal pores. 
The genus Heloderma, the only poisonous Lizard at present 
known, is very closely related to the Anguide, but well deserves to 
rank as a distinct family, on account of certain cranial peculiarities 
and the shape of the interclavicle. Its range is restricted to the 
western parts of Central America, from the Isthmus of Tehuantepec 
to as far north as New Mexico. 
* Quoted from an advanced separate copy. 
