RESEARCH SEMINAR. 319 



The juvenile plumages of the two species present the same 

 general pattern, but differ in detail. In both the ventral plum- 

 age is essentially pure white, doitgalli showing a faint rosy tint. 

 All dorsal feathers are pure white at the base, then, except the 

 remiges and rectrices, which are nearly like the adult feathers, a 

 pearl-gray area, followed by a dusky area, and all feathers with 

 a tawny tip. The inner tertiaries and their lower coverts, and 

 the lower rows of scapulars, have an added area of tawny and of 

 dusky colors. Thus the tawny and dusky areas of the nestling 

 downs are reproduced in the juvenile feather, with the addition, 

 at the inner half of the juvenile feather, of an area of pearl-gray 

 and a white base. The pearl-gray area corresponds in color to 

 the color of the adult feather. 



In hirundo these markings produce a barred effect, except on 

 the head, which is white at the base of the bill, gradually dark- 

 ening to black on the crown and occiput. In dougalli the outer 

 tawny and dusky areas are parallel to the border of the feather, 

 in the more strongly marked feathers, for fully a third of the 

 length of the feather, and therefore present a more mottled pat- 

 tern. Some feathers are even distinctly barred with dusky color 

 about their outer third. 



The essential pattern of the two plumages is, therefore, a defi- 

 nite barring of each feather on the dorsal surface, and a lack of 

 any marking on the ventral surface. The greatly modified rem- 

 iges and rectrices closely resemble the adult remiges and rec- 

 trices, thus requiring no transition stage, but the rest of the dor- 

 sal plumage undergoes a distinct transition from the nestling to 

 the adult, the intermediate, or juvenile plumage, resembling the 

 nestling plumage for its outer half, at least, and the adult plum- 

 age for its basal half. 



August 7. The Internal Factors of Regeneration in Alpheus. 



By CHARLES T. BRUES. 



Alphcus is a small decapod crustacean in which one of the 

 chelae is larger than the corresponding one on the other side. 

 When one of the larger chelae is cut off at the base, it has been 

 shown by Przibram, and also by Wilson, that its stump regener- 

 ates a chela of the small type, while the originally small one is 



