310 BARBOUR: ZOOGEOGR.\PHY. 



Ameiva taeniura Cope. 

 Cope, Proc. Acad. nat. sci. Phila., 1862, p. 63. Boulenger, Cat. lizards Brit, inus., 1885, 2, p. 350. 



The types, three fine specimens (M. C. Z., No. 3,614), were the only examples 

 in the collection until 'the receipt of many from Diquini and Manneville collected 

 by Mr. W. M. Mann. The species is confined to Haiti. 



Ameiva vittipunctata Cope. 

 Cope, Proc. Acad. nat. sci. Phila., 1S71, p. 220. Boulenger, Cat. lizards Brit . mus., ISSo, 2, p. 355. 



The types of this species came from near the city of San Domingo. Re- 

 cently, however, the Museum has received a fine suite of specimens from Mo- 

 mance, Diquini, and Manneville, collected by Mr. W. M. Mann. 



Ameiva maynardi G.vrman. 

 Carman, Bull. Essex inst., 1888, 20, p. 110. 



This form, derived from Haiti, occurs upon Great Inagua in the southern 

 Bahamas. The types are M. C. Z., No. 6,225. 



Ameiva exul Cope. 



Cope, Proc. Acad. nat. sci. Phila., 1862, p. 66. Stejneger, Kept. U. S. nat. mus. for 1902, 1904, p. 612, 

 fig. 59-66. 



This ground lizard is rather more wide-ranging than many of the species 

 of the genus. Various students, notably Stejneger, have compared specimens 

 from the different islands; and they find them apparently indistinguishable 

 upon Porto Rico, Vieques, St. Thomas, St. John, St. Croix, and Water Island. 

 Nevertheless, Garman (Bull. Essex inst., 1887, 19, p. 11) says, "Porto Rico 

 specimens appear to be a little lighter in color, more red on the back and head, 

 and have the whitish frecklings on the hinder part of the body and the base of 

 the tail, as also the dark spots along the flank, less numerous and more distinct 

 than those from St. Thomas. The latter have the colors a trifle darker, more 

 olive, and the white spots and the black spots less faded." I have re-examined 

 the specimens, now more than twenty years older than when Garman studied 

 them, and I find the difference to be really striking. The series are probably 

 very different in life, and probably represent groups of individuals strongly 

 tending toward the formation of distinct species by isolation, by the constantly 

 increasing tendency of an isolated group of individuals to vary according to 

 latent peculiarities which become in succeeding generations increasingly patent. 



