°1906 J Clark, Pterylosis of Swifts and Hummingbirds. 91 



and is more or less separate from the dorsal tract; the lower cervi- 

 cal is also narrow and not divided so far up on the throat as even 

 in the swifts. Lateral cervical apteria are very evident. The 

 dorsal tract of the Caprimulgi is clearly derived from an ancestral 

 form in which the anterior and posterior portions were not equally 

 well developed; moreover the spinal apterium is not long and 

 narrow, but short and wide, with sharp lateral angles. Probably 

 the caprimulgine form is derived from such a condition as is shown 

 in Nitzsch's figure of Falco brachypterus , rather than from a form 

 like that of Cuculus. The humeral tracts in Cypseli and Trochili 

 are near the dorsal and there are some feathers connecting them 

 therewith, but in Caprimulgi the numerals are narrow and dis- 

 tinct, at some distance from the dorsal. The form and position 

 of the femoral tracts is clearly different in the Caprimulgi from 

 those in the Cypseli and Trochili, and the marked contraction of 

 the sternal tracts to form the ventrals is a minor characteristic of 

 the Caprimulgi. Some of the details in which the Cypseli and 

 Trochili agree are not the same in the Caprimulgi, as for example, 

 the black skin on the hand and the last three primaries being the 

 longest; the development of the alula and the presence of 12 or 

 more secondaries in Caprimulgi may also be mentioned, though 

 no weight should be attached to such differences taken by them- 

 selves. 



Bibliography. 



'40. Nitzsch, C. L. — System der Pterylographie. 



'88. Shufeldt, R. W. — Studies of the Macrochires, etc. — Jour. Linn. 



Soc, Zool., Vol. XX., pp. 299-394. 

 '92. Lucas, F. A. — Pterylosis (of Trochilidae) in R. Ridgway's The 



Humming Birds.— Rep. U. S. Nat. Mus. for 1890, p. 290. 

 '94. Clark, H. L. — The Pterylography of Certain American Goatsuck- 

 ers and Owls.— Proc. U. S. Nat. Mus., Vol. XVII, pp. 551-572. 

 :01. The Pterylosis of Podargus: with notes on the Pterylography 



of the Caprimulgi.— Auk, Vol. XVIII, pp. 167-171. 

 : 01. Thompson, D'Arcy, W. — On the Pterylosis of the Giant Humming- 



Bird (Patagona gigas). — Proc. Zool. Soc. London, 1901, pp. 311-324. 

 : 02. Clark, H. L. — Are Humming Birds Cypseloid or Caprimulgoid? — 



Science, N. S., Vol. XV, No. 368, p. 108. 

 : 02. Shufeldt, R. W. — Pterylosis of Humming Birds and Swifts. — 



Condor, Vol. IV, No. 2, p. 47. 

 : 02. Clark, H. L. — Communication. — Condor, Vol. IV, No. 3, p. 75. 



