106 LIZARDS OF THE PHILIPPINE ISLANDS 



Cope says:* 



No genus of Agamidse is found in America, where the Iguanidae represent 

 them. The two families present some interesting parallels, which show the 

 effects of identical causes in producing similar effects on the organism. 

 These parallels are seen in the depressed form of the terrestrial forms in 

 both families and the relatively compressed form of the arboreal types. In 

 both families the former have representatives with horny processes on the 

 head and on the scales of the body; and in both are types with horny spines 

 on the tail. Among arboreal forms we find genera of both families with 

 series of horny processes forming a median dorsal crest, and in others 

 a prolongation of the spines of the dorsal and caudal vertebrae, producing, 

 a like result. 



In many cases the similarity is so striking that specimens 

 from the two families might easily be referred to the same genus 

 without examination of skeletal and dental characters. 



The application of the name "iguana" to certain Agamidse 

 which occur in the Philippines is incorrect, as the Iguanidse are 

 confined to North, Central, and South America, and the West 

 Indies. The Agamidse are found in Australia, the East Indian 

 Archipelago, Asia, Africa, and Europe. They are unknown in 

 Madagascar and New Zealand. 



There are only four genera of this family known in the 

 Philippines. 



Key to the Philippine genera of the Agamidse. 



a\ Ribs much prolonged, supporting a winglike lateral dermal expansion 

 which is folded close to body when not flying.. Draco Linnaeus (p. 107). 

 a^ No winglike expansion. 

 6\ No femoral pores. 



&. A strong fold on throat; usually a crest on neck or body. 



Gonyocephalus Kaup (p. 130). 

 c\ No fold or only a slight fold on neck; gular pouch more or less 

 developed; tail extremely long, dorsal scales nearly equal. 



Calotes Cuvier (p. 136). 

 h'. Femoral pores present; toes lobate; a fan on tail. 



Hydrosaurus Kaup (p. 140). 



The food of these genera varies; the first three are insect- 

 ivorous while the last is, almost if not wholly, herbivorous. All 

 lay eggs, those of Calotes being spindle-shaped. The eggs of 

 Hydrosaurus are somewhat oval to round and are deposited in 

 sand or loose earth along streams and rivers. 



The genus Calotes is noted for the ability of certain of its 

 species to make rapid color changes; these changes take place 

 in some species, especially Calotes marmoratus and C. cristatellus, 

 with startling rapidity. 



* Report U. S. Nat. Mus. for 1898 (1900) 219. 



