666 



Bulletin American Museum of Natural History 



[Vol. XLVI 



Fig. 10. .4, Dorsal view of head of Sator a/igustus Dickerson, A. M. N. H. No. 5716. X 2.5 

 B, Throat of type of Sntor angustus, to show differentiation of scales at the gular fold. TJ. S. N. M No. 

 G4262. X 3. 



is no trace of the posterior fold or incipient collar, and the better develop- 

 ment of the anterior fold may be correlated with this fact. 



Phrynosoma blainvillii blainvillii Gray 

 Plate LIV, Figure 2 



Phrynosoma blainvillii Gkay, 1839, p. 96, PI. xxix, fig. 1 ; Stejneger and Barbour, 



1917, p. 57. 

 Phrynosoma blainvillii blainvillii Grinnell and Camp, 1917, p. 164. 



Range. — Southwestern California and northwestern Lower California. 



Lower Californian Records. — Valladares, Van Denburgh, 1895, p. 118; 

 Ensenada, San Telmo, Wasson's Ranch in San Rafael Valley, Van Denburgh, 1896, 

 p. 1005; Nochoguero Valley, United States boundary, Cope, 1900, p. 427; San Salado 

 and Trinidad, Meek, 1905, p. 12; Ensenada, Van Denburgh and Slevin. 1921a, p. 62. 



A specimen in the Biological Survey collection comes from Ojos 



Negros (U. S. N. M. No. 37583). 



Phrynosoma nelsoni, 1 new species 

 Plate LIV, Figure 3 

 Phrynosoma coronatum (non Blainville) Meek, 1905, p. 12. 



Diagnostic Characters. — Two lateral fringes of elongate scales; enlarged 

 gulars present; nostrils on the canthus rostralis; ventral scales smooth; temporal 

 and occipital horns well developed; a large subrictal spine, followed by a postrictal; 

 tympanum nearly concealed by folds of the neck; closely allied to P. blainvillii blain- 

 villii, from which it is distinguished by the smaller and rugose scales of the top of the 

 head, the fewer enlarged dorsal scales, and the larger and more strongly keeled scales 

 of the vertebral line. 



: Nanied for Dr. Edward W. Nelson, Chief, Bureau of Biological Survey, United States Department 

 of Agriculture, whose explorations in Lower California make this name especially appropriate. 



