EIGHTH ANNUAL REPORT. 147 



opportunities for observing the characteristics of these interesting 

 creatures. 



COLOR CHANGES. 



Certain lizards have always evoked popular interest because 

 of their colors and color changes. These characters are especially 

 noticeable in members of the family Chamceleontidce, and certain 

 species of the Iguanidce. The families evincing this variation of 

 hues among their species are among the minority. Such forms 

 as the Scincidce, the Lacertidce and the Anguidce show no intima- 

 tion of this character. Although the marked changes of color 

 occur in species possessing a fine, granulated scalation, there are 

 many species with large and well-developed scales, either smooth 

 or carinated, that momentarily vary in their hues. Usually, how- 

 ever, the variation in such individuals consists of an intensifica- 

 tion of a definite and permanent pattern, or the fading of the same. 

 An example of such species is the common Swift (Sceloporus un- 

 dulatus) and its allies. Patches of pale gray on the abdomen and 

 throat will assume the most brilliant shades of blue, while the 

 pattern on the creature's back varies from a series of transverse 

 dashes of gray to the same pattern in brown or yellow. 



It is not the writer's idea to describe these color changes from 

 a realistic standpoint, but rather to note the actual effects pro- 

 duced upon several species by certain conditions. The common 

 Chameleon (Chameleon vulgaris), of Africa, is an interesting 

 illustration. Numerous experiments have been conducted with 

 these lizards in the Reptile House, and the following is a list of 

 observations made upon them : 



Specimen No. i was placed in the sunlight in such a position 

 that only one side of the creature was exposed to the brilliant rays. 



Specimen No. 2 was placed at an angle to the sun so that its 

 rays suffused the entire reptile. 



Specimen No. 3 was placed in a perfectly dark box in a tem- 

 perature of 75 F. 



Specimen No. 4 was placed in a dark box in a temperature of 

 5o°F. 



After a quarter of an hour's time the following results were 

 noted : 



No. 1 was dark brown on the side exposed to the sun, and a 

 pale brown mottled with green on the shadowed side. 



No. 2 was of a yet darker brown than No. 1. 



No. 3, when uncovered, emerged in a brilliant coat of green. 



No. 4 crawled sluggishly about his chill quarters, showing a 

 uniform pale gray. 



