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ALTRiriAT, aHAM.ATOllKS— IIKUODIONES. 



Wuekish. YoHn(j: Uiiitorin, nithiT durk, Kriiyinh brown, the ruiiiii, iippur luil-coveits, bnsal hull' 

 ut'tuil, ami ciitiic lnwcr jiai'ts, iiiciinlin;; itxiilaix uixl lining of the wiii|;, iciiilinuoiis wliilt.' ; licail 

 mill iR'fk wtrt'iikud with dii^ky or t,'rayisli brown on a ;,'rayiHli or dull whitish yruiuid-color. 

 IVulhtrin); of thu huud t-xtunding forward alnioHt to thu hill ' 



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Length, about 24.00-26.00 ; t-xpnnse, about 40.00 ; winj?, 10.30-11.76 ; tail, 4.00-5.00 ; culmeii, 

 4.15-0.3O ; depth of bill, .(JO-.72 ; tarsus, 3.1(>-4.tHt ; middle toe, 2.16-2.70 ; bare portion of tibia, 

 2.(H)-2.80. 



In this species there is a range of individual variation not exceeded by nny member of the 

 family ; this variation affectin;,' not only size and relative proportions of the ditl'erent parts, but 

 also characters which have been accordi^l freneric or sub;,'enc'ric value. Thus, tukinj,' two perfectly 

 adult birds from localities jjeoj^Taphically near to^'ctlicr (.Ma/atlan and Tehuantepec, Western and 

 Southwestern Mexico), they represent veiy nearly, if not (iuite, the extremes of size, especially 

 as regards the bill ; one of them (Xo. .'i^tSlt), Mazatlan) having this member (>.30 inches in lengtii, 

 while in the other (No. .')!)773. 9 . Tehuantepec) it measures only 4.70. As to colors, they arc 

 identical, both being pure white, with the terminal portion of the four outer ])rimaries glos.iy 

 greenish-black. Tiiere is a most remarkabli! difference, however, between these two examjiles in 

 the anterior outline of the feathering of the head, which difference nuty be explained as follows; 

 In the Mazatlan specimen the frontal apex all iiut comes in contact with the base; of the culmen, 

 there being left between a space only about .(»") of an inch wide; in the Tehuantepec specimen there 

 is an interval left of .80 of an inch ! In the Mazatlan example, the anterior feathers of the throat 

 form a broad angle projecting forward into the bare gular skin for a distance of .00 of an inch ; in 

 the Tehuantepec specimen, their anterior outline has exactly the opposite form, being regularly and 

 deeply concave, so that the bare gular skin has a semicircular or regularly con\'ex posterior outline — 

 exactly as in fully adult specimens of E. ruber! In the former of these specimens the malar 

 feathers extend forward to within .2.5 of an inch of the rictus, or to much beyond the anterior 

 angle of the eye ; while in the other they approach to within only about .70 of the rictus, scarcely 

 reaching to below the middle of tlu eyes. 



Other characters in which the Tehuantepec example differs from the one from Mazatlan, consist 

 in the subterminal portion of the bill being black for the space of nearly two inches, and in the 

 distinct serration of the middle portion of the tomia. These extremes of variation are noticeable 

 among skins obtained during the breeding sc^ason in Florida, specimens from the same breeding 

 grounds differing as much as the two described above. 



Immature specimens show, according to age, all possible stages of plumage intermediate be- 

 tween the pure white adult and gray young. 



The White Ibis is a resident only in the more southern portions of the United 

 States, though it not unfrequently occurs as a straggler in various places farther 



• Accoi-diiig to Auihibon, "the young birds arc at first covered with thick down of a dark gray 

 color." 





