8 PROCEEDINGS OF THE NATIONAL MUSEUM vol.73 



140. — Stejneger and Barbour, 1917, Check list N. Amer. Amph. Rept., 

 ed. 1, p. 44; 1921, Proc. New Eng. Zool. Club, vol. 7, p. 82. — Van Dbnburgh, 

 1922, California Acad. Sci. Oc. Papers No. 10, Reptiles of West. N. Amer., vol. 

 1, p. 64. — Stejneger and Barbour, 1923, Check list N. Amer. Amph. Rept., 

 ed. 2, p. 42. 



Uromastyx Merrem, 1820, Tent. Syst. Amph. (Part), p. 56, 1820. — Gray, 1845, 

 Cat. Lizards Brit. Mus., p. 191. 



Cyclura Harlan, 1824. Journ. Acad. Nat. Sci. Philadelphia, vol. 4 (Part), p. 

 250.— Gray, 1827, Philos. Mag., ser. 2, vol. 2, p. 57 (Part).— Wiegmann, 1834, 

 Herp. Mex., pp. 15, 41 (Part). — Dumeril et Bibron, 1837, Erp6t. Gen., vol. 4, 

 p. 214-244 (Part).— Fitzinger, 1843, Syst. Rept., p. 56 (Part).— Gray, 1845, 

 Cat. Lizards Brit. Mus., vol. 2, p. 190 (Part).— Cope, 1868, Proc. Acad. Nat. 

 Sci. Philadelphia, p. 283 (Part).— Heilprin, 1882, Proc. Acad. Nat. Sci. Phila- 

 delphia, p. 333 (Part). — Chapman, 1891, Proc. Acad. Nat. Sci. Philadelphia, 

 p. 366 (Part). 



Enyaliosaurus Gray, 1845, Cat. Lizards Brit. Mus., p. 192. 

 . (Jachryx Cope, 1866, Proc. Acad. Nat. Sci. Philadelphia, p. 124. — Cope, 1885, Proc. 

 Acad. Nat. Sci. Philadelphia, vol. 23, pp. 262-270.— Boulenger, 1885, Cat. 

 Lizards Brit. Mus., vol. 2, pp. 195-198. 



Diagnosis oj the genus. — The members of this genus have the tail 

 armed w^ith strong spinous scales; tympanum distinct, nearly as large 

 as orbit. The body is scarcely compressed; the scales of the median 

 dorsal row enlarged, forming a dorsal crest. Scales of head and body 

 small, those of the belly being smaller than those of the upper head, 

 and those of the back being smaller than those of the belly. A very 

 strong transverse gular fold, except in two species in which there is a 

 large nondilatable longitudinal gular fold, the dewlap. There is a 

 short series of femoral pores. Mandibular and maxillary teeth pleu- 

 rodont, the lateral teeth only with denticulated crowns; pterygoid 

 teeth present. The tongue is short and thick and slightly notched 

 anteriorly, nonpro tractile. Digits compressed, with keeled lamellae 

 inferiorly, but without corneous combs or pectinations on the toes. 



Of the 27 species that have been described only 13 are valid. They 

 are G. acanthura (Shaw), 1802; hakeri Stejneger, 1901; hrachylopTia 

 (Cope), 1866; hrevirostris Cope, 1886; clarM Bailey, 1928; defensor 

 (Cope), 1866; erythromelas Boulenger, 1886; hemilopha (Cope), 1863; 

 palearis Stejneger, 1899; parkeri Bailey, 1928; pectinatal^iQgm.&mi, 

 1834; similis (Gray), 1831; quinquecarinata (Gray), 1842. These, 

 may be separated by the use of the following key to the species: 



KEY TO THE SPECIES OF CTENOSAURA 



A'. — Median row of dorsal scales enlarged and extending from nape to end of 

 tail, without interruption at the sacrum. These scales are usually large 

 and armed with heavy spines, more pronounced in the males than in the 

 females. Over the sacrum the crest consists of slightly raised and enlarged 

 scales without spines. 



B^. — Head very short, rostrum conspicuously decurved brevirostris 



B2. — Head normal, rostrum not conspicuously decurved. 



C — First six whorls of spinous scales of the tail separated from each 

 other by four or more rows of small, fiat, smooth scales — parkeri 



