CHAPTER XVI: THE SWIFTS 



Two Genera — UTA and SCELOPORUS — Small, Rough-scaled 



Lizards 



Inn genera Ula and Sceloporus are closely allied. All of 

 the species are of small or very moderate size. Those of the 

 former genus may be termed the Sniall-scaled Swifts, owing to 

 the minute character of the scales covering the greater portion 

 of the back, while the species of Sceloporus may appropriately 

 be considered under the title of the Spiny Swifts, as their scales 

 are large, coarsely keeled, and terminate in sharp points of a 

 bristling character. 



The species of both genera appeal to one another in 

 form, though the species of Uta are the most slender as a 

 rule and have proportionately longer tails than the Spiny 

 Swifts. Uia is essentially a genus of the southwestern 

 United States and northern Mexico, while the species of 

 Sceloporus are widely distributed, occurring in the central 

 and southern latitudes of the United States, from the At- 

 lantic to the Pacific Ocean and abounding throughout Mexico 

 and Central America. 



The Small-scaled Swifts, Uia: Sixteen species of this 

 genus are recognised. The body is rather stout and flattened; 

 the head is proportionately quite small. With some species 

 the tail is of moderate length; with others, very long and slender. 

 The greater area of the back and sides is covered with very small 

 scales, but some species have enlarged rows of scales on the cen- 

 tral portion of the back. The generally minute scalation at 

 once distinguishes the members of this genus from Sceloporus — 

 the latter having large, coarsely keeled and sharply pointed 

 scales over the entire upper surface. The few rows of large, 

 keeled scales seen on the central portion of the back of many 

 species of Uta, resemble the general scalation of the Spiny Swifts. 

 Many of the species of Uta have coarse, spiny scales on the tail 

 like the members of Sceloporus. One of the striking points of 

 similarity to be observed with species of both genera is a colour 



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