78 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



(Gadow), is produced at will in the mid- ventral region of the head 

 and neck. This fan is produced by the hyoidean apparatus. The 

 mechanism of this apparatus consists of a double, tapering car- 

 tilage lying in the mid-ventral line and attached to the body of 

 the hyoid just anterior to a line through the center of the eye. 

 When erected, it carries the loose skin of the cervical region with 

 it. 



This throat-fan is, according to Ditmars, purely ornamental 

 and produced only by the males, being accompanied by a vigorous 

 nodding of the head and neck. 



It is produced when a male spies a female or when it prepares 

 for combat with another male. When the males are captured and 

 held in the hand, this fan becomes prominent. Often when two 

 males meet, each one will erect a ridge along the mid-dorsal line 

 extending from the base of the occiput to a variable distance along 

 the back. This may be accompanied by a marked lateral com- 

 pression of the thorax and abdomen so that the lateral diameter 

 is smaller than the dorso-ventral, whereas under ordinary condi- 

 tions the reverse is true. The throat-fan is usually very prominent 

 during this state and there is present a characteristic coloration 

 which will be described later. 



The Anolis lives well in captivity when supplied with water in 

 the form of scattered droplets and flies or meal worms. It soon 

 becomes apparently very tame and will take insects from the 

 fingers of its captor. 



Observations of Color Changes in the Living 



Anolis 



A general fact impresses itself after one has captured and 

 observed many of these lizards in captivity, namely, that the range 

 of variation in the color of the skin is by far greater in those animals 

 which have been freshly captured. After a few weeks of captivity, 

 although seemingly in perfect health, the color changes become 

 less complicated and less brilliant. This observation may tend to 

 explain the differences noted by different observers as to the color 

 changes. Ditmars states that the color varies from different 

 shades of brown to emerald green and that although these are the 

 common hues of Anolis, other hues are striking, namely, golden 

 yellow and slaty gray with the peppering of white spots over the 

 back. These colors he believes occur during the transition from 

 the two extremes, namely, brown and green. Carlton states that 



