Henninger — Ox Birds of Seneca County, O. 47 



The color pattern of the downy younig is outlhied when the 

 down feathers first make their appearance upon the skin sur- 

 face of the six-day embryo. That is, the pigment begins to 

 develop in the down feathers which are to be black almost as 

 soon as the feather papilla appears vipon the skin surface. An 

 entire down feather is seldom all one color, but those which 

 are black at the tip are tawny in the middle and black at the 

 base, and those which are tawny at the tip are also black at 

 the base. This applies only to the down feathers of the dorsal 

 .surface. There are many down feathers on the ventral sur- 

 face which are wholly white. 



Taking the three plumages as illustrating a process of evolu- 

 tion of color pattern, and taking the streakiness of the downy 

 young of dougalli as the more primitive, we may readily per- 

 ceive that longitudinal stripes of color break up into transverse 

 bars, and the bars give place to a uniform distribution of color. 

 In the evolution of the present adult coloration of the terns of 

 the genus Sterna, it seems probable that a primitive longitudi- 

 nal streaking becamie broken up into longitudinal series of spots 

 which were arranged in transverse series so as to give the ap- 

 pearance of broken bars ; these series of spots extended lateral- 

 ly, fused, and so became in reality transverse bars, which, 

 spreading and finally fusing, resulted in the uniform coloration 

 of the dorsal region in Sterna adults. Such a transition would 

 be in complete conformitv to the law announced bv Eimer 

 ('82). 



A PRELIMINARY LIST OF THE BIRDS OF SENECA 

 COUNTY, OHIO. 



BY W. F. HENNINGER. 



The need of a new county list of birds in Ohio may be 

 questioned, with two excellent state lists — Jones' and Dawson's 

 — of recent issue; but it is only after every county in the 

 state has been, worked over with care that we shall feel war- 

 ranted in saying that any list is more than preliminary in char- 

 acter. And if this county list, though bv no means exhaustive 



