694 Bulletin American Museum of Natural History [Vol. XLVI 



A specimen in the Biological Survey collection, U. S. N. M. No. 

 37514, from the Cocopah Mountains, east base, is the first record of this 

 form from Lower California. 



The lateral light line is plainly on the third and fourth scale rows 

 anteriorly. The dorsal scale formula is 23-21-19-17; ventral plates, 

 152; subcaudals, 41 +; preoculars, 1-1; upper labials, 8-8; lower 

 labials, 10-10. 



The occurrence of this form in northern Lower California is not 

 surprising in view of its occurrence at Yuma. 



Key to the Species of Thamnophis in Lower California 



1. Dorsal light line present 2. 



No dorsal light line T. ordinoides hammondii. 



2. Lateral light line anteriorly on the third and fourth scale rows. . . . T. megalops. 

 Lateral light line anteriorly on the second and third scale rows. 



T. ordinoides vagrans. 



Sonora episcopa (Kennicott) 



Lamprosoma episcopum Kennicott, 1859, p. 22, PI. vm, fig. 2. 

 Sonora episcopa Stejneger and Barbour, 1917, p. 92. 



Range. — Texas to southeastern California, south into Mexico. 



Lower Californian Records. — Cape St. Lucas, Baird, 1S59, p. 299; Santa 

 Rosalia, Mocquard, 1899, p. 319 



Chilomeniscus stramineus Cope 

 Chilomeniscus stramineus Cope, 1860a, p. 339; Stejneger and Barbour, 1917, p. 94. 



Range. — Southern Lower California. 



Lower Californian Records. — Cape St. Lucas, Cope, 1860a, p. 339; La Paz, 

 Yarrow, 1882, p. 86; San Jose del Cabo, Miraflores, Van Denburgh, 1895, p. 138; 

 San Marthe, Cope, 1900, p. 950. 



Four specimens in the present collection, one from Cape San Lucas 

 (A. M. N. H. No. 5578), three from Miraflores (A. M. N. H. Nos. 5574- 

 5, U.S. N.M. No. 64579). 



These specimens show very little variation; the dorsal scales are 

 uniformly in thirteen rows; ventral plates (in the order named) 109, 117, 

 113, 121; subcaudals 24, 25, 28, 25; rostral in every case separated from 

 the prefrontals and the nasals from the preoculars. The largest speci- 

 men (5578) measures 230 mm., tail, 32 mm. 



Chilomeniscus ephippicus Cope 

 Chilomeniscus ephippicus Cope, 1867a, p. 85; Stejneger and Barbour, 1917, p. 93. 



Range. — Southern Lower California to the Colorado Desert, reaching Tucson, 

 Arizona, to the east. 



Lower Californian Records. — La Paz, Yarrow, 1882, p. 86; Santa Rosalia 

 and Mulege, Mocquard, 1S99, p. 317; San Fernando, Cope, 1900, p. 951; Todos 

 Santos. Van Denburgh and Slevin, 1921a, p. 70. 



