220 BULLETIN 15 4, UNITED STATES NATIONAL MUSEUM 



stripes in larger specimens, thus increasing the irregularity of their 

 outline; back never with fine reticulations. 



A summary of data taken on the 115 available specimens of this 

 species follows: Body, 58-135 mm.; tail, 156-340; total length, 21G- 

 470; length of tail as percentage of total length, 07.7-74.0; width of 

 head, 9.0-21.5; Avidth of head as percentage of body length, 11.9-17.3; 

 hind leg, 44-85; length of hind leg as percentage of body length, 

 G3. 5-76.0; frontoparietals 1 in 2 specimens, 2 in 112 specimens, and 

 3 in 1 specimen; supraoculars 4 in 112 specimens and 5 in 3 speci- 

 mens; supraocular granules extending as far forward as the center 

 of the third supraocular in 37 specimens, to the anterior border of 

 the third supraocular in 67 specimens, to the middle of the second 

 supraocular in 5 specimens, to the anterior border of the second supra- 

 ocular in 4 specimens, and to the middle of the first supraocular in 1 

 specimen. 



According lo the original description (Cope, 1863, p. 104) this 

 species has the collar scales largest at the edge, but an examination 

 of a number of specimens shows that these scales are normally 

 largest medially. Ditmars (1907) was apparently in error in saying 

 that " large adults lose all traces of stripes." 



Range. — The giant whiptail occurs in the Cape District of Lower 

 California from Cape San Lucas northward to La Paz Bay, and pos- 

 sibly to Magdalena Bay as well. The availble reports follow : {Agua 

 Caliente^ Van Denburgh, 1922, p. 508, C.A.S. ; Buena Vista., Van Den- 

 burgh, 1922, p. 508, C.A.S. ; Cape San Lucas, Schmidt, 1922, p. 677, 

 U.S.N.M., C.A.S.; Espiritu Santo Island, Schmidt, 1922, p. 677, 

 U.S.N.M., C.A.S. ; Guamuchil Rancho, Van Denburgh, 1922, p. 508, 

 C.A.S.; Isla Part Ida, near Espiritu Santo Island, C.A.S.; La Paz, 

 Yarrow, 1882, p. 42, U.S.N.M., C.A.S.; Magdalena Bay, Loekington, 

 1880, p. 295 ; Mirafores, Van Denburgh, 1895, p. 125, C.A.S. ; San 

 Antonio, Van Denburgh, 1922, p. 508, C.A.S. ; San Bartolo, Van Den- 

 burgh, 1922, p. 508, C.A.S. ; San Bernardo Mis., Schmidt, 1922, p. 677, 

 U.S.N.M.; San Jose del Gala, Van Denburgh, 1895, p. 125, C.A.S., 

 Stanford ; San Pedro, C.A.S., M.C.Z., INIich. ; Sierra San Lasaro, Van 

 Denburgh, 1895, p. 125, Stanford; Todos Santos, Van Denburgh, 

 1922, p. 508, C.A.S.; Triunfo, Van Denburgh, 1922, p. 508, C.A.S.). 



Habitat and habits. — Very little is knoAvn about the habitat and 

 habits of this species. " It was one of the common lizards of the 

 lower levels, but it was not seen at a greater elevation than at 

 Guamuchil Eancho, 1800 feet (Van Denburgh and Slevin, 1921, 

 p. 62). * * * Not always relying on brush for shelter, they 

 often run across large open spaces, depending on their speed to 

 escape an enemy." " This lizard, like others of the genus, is ex- 

 tremely swift when frightened (Van Denburgh, 1922, p. 508). Mr. 



