NOTES OX K.MI5l{VOS 



323 



and the two outer rows (liver<>e slii>litly to come to^'ether at 

 the base of the neck, wliere they continue parallel to the head. 



Tlie inferior tracts consist of two thick rows of sheaths 

 extending along either side of the abdomen, which come to- 

 getlier above the furcula. A dense ])atch fills the apterium 

 over the lower sternum and upper abdomen. 



The head is more or less re"ulaidv covered with i-ows 

 which extend to and surround the nostrils. The eye is en- 

 circled by a widely separated double row of long feathers 

 which connect with the nostril ring by a single row, and the 

 eyelid is fringed with short sheaths. From the nostrils, run- 

 ning along the groove above the eye, is a double row, and 

 midwav between the eyes a tiiple line which extends straight 

 back until just in front of the parietal region, where the outer 

 lines diverge and gradually round together again to enter 

 the spinal tract. The middle line passes into the open space 

 thus formed, where two other rows run parallel with it to 

 the spinal tract. A single line runs behind the auditory aper- 

 ture and joins the ventral tract. The aperture itself is mar- 

 gined with short feathers. (Fig. 110.) 



FIG. 110. HEAD PTERYLOSIS OF AN EMBRYO DUSKY NIGHTHAWK 



