320 DR. H. GADOW OX EVOLUTION [Mar. 20, 



rows of tibial plates, both have the posterioi- border of the collar 

 formed by complete rows of granular scales, and both have a, long 

 preanal isthmus covered with many small scales. The Rincon 

 specimen has 17/20, the Balsas specimen 19/18 femoral pores. 

 Consequently both are exceptional, aberrant of their own kind 

 taking on the typical features of the other species. If it were not 

 for the pattern and coloration, which in the Rincon specimen are 

 decisive, the decision would lie with the femoral plates, which in 

 their numbers agree with one, in their extension to the knee 

 with the other species ! 



Cnemidophorus guttatus Wiegmann. 

 (Text-figs. 67, 74, & 75.) 



Hater led examined 61 specimens, from the following localities :— 

 15 Agua fria, western border of State of Vera Cruz. 

 2 San Juan Evangelista, State of Vera Cruz. 

 4 La Antigua, near Yera Cruz. 

 1 " Vera Cruz." 



22 typical C. guttat-us, all from the Atlantic Tierra Caliente. 



1 Salina Cruz.* 



1 San Mateo del Mar.* 



4 Tequesixtlan.* 



4 San Geronimo*, Isthmus. 



4 San Domingo de Guzman*, Isthmus. 



4 Cocoyul.* 



4 South of and at San Luis Allende. 



1 Miahuichan.* 

 11 Ayutla. 



2 Tierra Colorada. 



3 South slope of Cajones.* 



39 from the Pacific Tierra Caliente. Those marked * are the 

 more typical C. immutahilis . 



Size, from nose to vent. — Any Guerrero specimen above 100 mm. 

 is a fairly large male ; near the Isthmus and in the Atlantic Hot- 

 lands both sexes reach a larger size, and one giant male from San 

 Domingo measures 138 mm. The smallest ai-e those of the 

 inland districts of Guerrero, from Los Cajones to Ayutla and San 

 Luis Allende. 



S'upraoculars, normally 3, the space behind filled with numerous 

 granules. About 1 2 to 14 per cent, are exceptional : three specimens 

 out of the four from Tequesixtlan, one with 4/3, another with 4/4, 

 and the third with 5/5, due to an extra rather large scute in front 

 and behind the normal plates. Similar irregularities occur iir 

 the typical C. guttatus, for instance from Agua fria, with 3/4 

 or 4/3. 



Collar (text-fig. 65 A) as in C. cleppei, but the enlarged scales 



