332 DR. H. GADOW ON EVOLUTION [Mar. 20, 



It is important to note that San Juan lies close to, and between, 

 Monterey and Montemorelos, from both of which places some of 

 Cope's C. gularis gularis ai'e said to have been received ; and that 

 he mentions Monterey specimens as having the low nrxmber of 

 pores. To judge from the specimens described below, it seems to 

 me that this is the critical district in which the change from the 

 typical gularis into the slightly more southern var. ineeki is taking 

 place. This can be settled definitely only by examination of the 

 specimens in the Smithsonian Institution. 



The following specimens I distinguish as C. gularis, var. 

 meeki : — 



Two sjjecimens from Montemorelos, collected by Dr. Meek. — 

 One 62, the other (male) 65 mm. in length, agree in coloration and 

 patte]!! with the typical var. meeki, but the collar is distinctly 

 weaker, the scales decreasing rapidly towards the sides. There is 

 only a nest of moderately large scutes on the forearm ; the scutes 

 being distinctly less developed than in the San Juan specimens. 

 Humerus with 6 rows of scales, all rather large. Femoral rows 

 5 to 6 iri'egular in one, 6 to 7 irregular in the other. S with 

 16/15, the smaller specimen with 19/20 pores. The frenocular is 

 present in one, absent in the other. 



Six specimens from Garza Valdez, collected by Dr. Meek. — 

 60-75 mm. in length ; two females with eggs measure 64 and 

 68 mm. Consequently a decidedly small kind of lizard. 



Frenoculars present in 3, absent in 3 specimens. 



Collar composed of large scales, except in one specimen in which 

 the scales are rathei* small ; rarely with a few scattei'ed granules 

 on the posterior edge. 



Humerus with only 5 or 6 rows of scales, which, in conformity 

 with their small number, are all rather large. 



One or two of the last rows are continued upon the forearm's 

 posterior side. 



Forearm : front with 2|, rarely 3 rows of scutes. The posterior 

 surface is covered with at least one row of very large scutes. 



Femur with 6 rows of scales, of which three extend down to 

 the knee. 



Tibia with 3 rows of scutes, with sometimes a small fourth on 

 the fibular side. 



Pores : 4 specimens with 15/16, one with 17/18, one with 19/19. 



Coloration of under pai'ts : Throat bluish white in young and 

 in females ; in males with a j^ink tinge and faintly mottled with 

 bluish pigment on the sides. Collar white, but mottled on the 

 sides in the males. Chest and abdomen in young and females 

 white, suffused with bluish on the sides ; this suffusion increases 

 in males first on the chest and then spreads backwards, until in 

 the old males all the under parts inclusive of the arms and thighs 

 are uniform black. Under surface of tail and tibia uniformly 

 yellowish white. — Upper surface with 3 pairs of white or bluish- 

 white stripes. The fields ai-e nearly black, with rather faint 

 bluish or whitish spots in the first and second fields. The mid- 



