PHALACROCORACID.E — THE- CORMORANTS — PHALACROCORAX. 151 



Similar to the above, but tufts of the head wanting, and the bare skin of the lores, gular pouch, 

 etc., deep yellow instead of orange, and the blue of the mouth and eyelids absent. Young, first 

 plumage : Head and neck grayish brown, lighter next to the gular sac, darker on the crown and 

 nape ; baok, scapulars, and 

 wings, dull brownish gray, 

 the feathers bordered with 

 dusky brown ; rump dusky 

 brown ; primaries and tail 

 dull grayish black ; lower 

 parts light fawn-color, dark- 

 er on the sides, anal-re- 

 gion, and crissum. Bill dull 

 brownish yellow, nearly 

 black on the culmen ; gular 

 sac deep chrome yellow ; 

 iris greenish gray ; legs and 

 feet deep black. Yninnj, in 

 ir in h r : Similar to the above, 

 but throat, jugulum, and 

 breast paler, sometimes quite 

 white. 



Total length, about 29 

 to 33 inches ; extent, 45 to 

 55 ; wing, 11.20-14.00 ; tail, 

 5.60-8.50 ; culmen, 1.90- 

 2.55 ; tarsus, 2.05-2.90 ; 

 longest toe, 3.05-3.75. (A 



P. dilophus, nuptial dress. 



marked increase of size to the northward.) 



A very careful examination and comparison of more than fifty examples of these birds, very 

 clearly proves the identity of the three supposed species respectively called by authors P. dilo- 

 phus, P. fiuridanus, and P. cincinnatus, the latter representing a very marked geographical modi- 

 fication of color ; the 

 so-called fiuridanus, on 

 the other hand, repre- 

 senting merely a slight 

 modification of size. 

 The examination in 

 question shows the 

 geographical variation 

 in this species to be 

 of two kinds, viz. : (1) 

 A more or less marked 

 increase of size to the 

 northward, and (2) a 

 gradual change from 

 uniform glossy black 

 nuptial crests, in east- 

 ern birds, to crests 

 entirely pure white, or 

 with merely a slight 

 admixture of black, 



bare space on the head, and gular sac, rich orange. Feet and claws black." "P. floridanus : " — " Adult 

 male, in spring : Upper mandible black, along the basal margins blight blue ; lower blight blue, curiously 

 spotted with white. Iris light green, margins of eyelids light blue, spotted with white. Bare space on 

 the head and gular sac rich orange. Feet and claws grayish black." 



P. dilophus cincinnatus, nuptial dress. 



