1901.] PIEEYLOSIS OF THE GIANT HUMMING-BIRD. 323 



111 Collocalia the interramal area is continuous with a feathered 

 area which occupies the front of the neck to the level of the shoulders, 

 the feathers here pointing towards the middle line, where they are 

 divided by a narrow median apterion. The dorsal tract has a small 

 lanceolate median apterion, in front of which it runs more than 

 halfway up the neck to form a median shoulder-patch of strong 

 stiff feathers ; it covers, much more closely than in the Humming- 

 bird, the sides of the body, the outer surface of the thigh, and the 

 rump, also the base of the oil-gland in its middle line, where, 

 indeed, the feathers are very stiff and strong. 



The pectoral tracts are widely separate in the middle line, and 

 are further separated from the feathering of the neck, so that 

 here the feathering of the head and neck is entirely cut off from 

 that of the body. On each side of the breast is also a long narrow 

 lateral apterion, which is only prevented from communicating with 

 the apterion of the neck by a single row of feathers that run 

 inwards from the humeral tract to the sides of the shoulder-patch. 



On the leg we have no well-defined femoral tract, which may, 

 however, be represented by a single row of about seven feathers, 

 imperfectly differentiated from the dorsal tract. The outer and 

 inner surfaces of the leg are bare, but on the tibia there is a band 

 of feathers on the edge of the leg in front and behind, which two 

 bands unite at the ankle and are continued down the front of the 

 tarsus. 



The tail consists of ten rectrices, each with a corresponding 

 upper and lower covert, the lower row of coverts, however, con- 

 taining two additional outer feathers on each side. 



The anus is crowned with a circlet of long feathers. The oil- 

 gland, as is well known, is unfeathered. 



In Caprimulgus the feathering of the back of the head is 

 continued into a narrow posterior cervical tract, three rows broad, 

 without either the posterior cervical apterion of Patagona or the 

 interruption seen in Collocalia. The posterior cervical tract, which 

 is placed on a median fold of skin, as in Pycraft's description of the 

 Owls, divides over the shoulders into two narrow bands which unite 

 with similarly formed extensions of the dorsal tract to enclose a 

 small diamond-shaped apterion and to form a dorsal saddle much 

 less extensive than in the Humming-bird. There are well-marked 

 femoral tracts, and scattered feathers between them and the dorsal 

 tract. The inferior cervical tract divides near the middle of the 

 neck, and gives off a branch to the prepatagial border of the wing 

 and shoulders, as it merges into the pectoral (or ventral) tract on 

 each side. The median branch between these two, broad and 

 characteristic in the Owls, is not present. 



The pectoral tracts are wide apart, and somewhat narrower, and 

 they contract a little way in front of the posterior edge of the 

 sternum into narrow bands that run backwards curving in 

 towards the anus. 



The pterylosis of the neck differs much, therefore, in the three 

 birds described, the narrow posterior cervical tract and broad lateral 



