20. PLESTIODON 577 



the tail is bright blue. The entire lower surfaces are light 

 blue with some yellowish white on the hind limbs and tail 

 and rarely on the belly. 



Length to anus 42 50 59 61 63 65 



Length of tail 113 131 171 169 168 180 



Snout to ear 10 12 15 15 15 15 



Snout to interparietal 



plate 8 10 12 12 12 13 



Width of head 7 7^ 9 9 9 10 



Fore limb 16 18 22 22 23 21 



Hind limb 31 36 44 43 43 45 



Snout to intcrparietal 



fourth toe 15 17 20 19^ 20 20 



Distribution. This species is native to Monserrate 

 Island, Lower California, Mexico. 



Family 9. SCINCID^ 



The tongue is slightly notched at its tip. The head is 

 covered with large, regular plates. The scales on the body 

 and tail are moderately large, imbricate, and reinforced with 

 an armor of bony plates. The eyes have round pupils and 

 well-developed lids. Femoral pores are absent. Limbs may 

 be either present or absent. An interoccipital plate is rarely 

 present. A single genus represents this family in western 

 North America. 



Genus 20. Plestiodon 



Eumeces WIEGMANN, Herp. Mex., 1834, p. 36 (part). 



Plestiodon DUMERIL & BIBRON, Erpetologie Generale, Vol. V, 1839, 



p. 697 (type, quinquelmeatus) . 

 Lamprosaurus HALLOWELL, Proc. Acad. Nat. Sci. Phila., 1852, p. 206 



(type, guttulatus). 



The limbs are four, pentadactyle. The dorsal, lateral, 

 caudal, and ventral scales are thin, smooth and strongly im- 



