II. SATOR 259 



56. Sator grandaevus Dickerson 

 Ceralbo Island Sator 



Sator grandavus Dickerson, Bull. Amer. Mus. Nat. Hist., Vol. XLI, 

 1919, p. 469 (type locality, Cerralvo Island, Gulf of California, 

 Mexico); Nelson, Mem. Nat. Acad. Sci., Vol. XVI, 1921, pp. 

 114, 115, 171. 



Description. — Body and tail somewhat compressed j 

 snout low, rounded and rather long; nostrils large, opening 

 upward and outward nearer to end of snout than to orbit. 

 Head plates large, smooth, nearly flat or slightly convex, 

 interparietal largest; frontal not divided transversely; four 

 to six enlarged supraoculars, separated from the frontals, 

 frontoparietals and parietals by one or two series of gran- 

 ules. Superciliaries long, narrow, imbricate and projecting. 

 Central subocular very long, narrow and strongly keeled. 

 Rostral and supralabials long and low; usually six, or some- 

 times seven supralabials. Symphyseal large, followed by a 

 series of large plates separated (except first) from the in- 

 fralabials by one or two series of moderately enlarged sub- 

 labials. Gular rgion covered with small, smooth, imbricate, 

 rounded scales which change gradually to granules on sides 

 of neck. Usually a transverse line of smaller scales across 

 throat and sometimes at this point a more or less well de- 

 veloped or rarely strong gular fold. A patch of enlarged, 

 keeled upper temporals. Ear denticulation short, of two to 

 four scales, the largest exceeding in length diameter of lar- 

 gest plate in front of ear. Back covered with fairly large 

 scales of nearly uniform size, in parallel rows, becom- 

 ing rather abruptly smaller or granular on sides of body; 

 dorsal scales very strongly keeled, imbricate, shortly muc- 

 ronate, with entire posterior edges; 56 to 69 scales in a row 

 from interparietal plate to backs of thighs; average in 30 

 specimens 62.93. Scales on lower surface of body a little 



