Pteryloyraphy of the Tiiiamiformes. 3 



margin, for about half its length, has blended with the 

 pt. spinalis. At the shoulder-joint it gives off a short 

 thick branch to the pt. humeralis above^ and passes below 

 into the pt. ventralis. 



Pt. vetitralis. — This is divided into a strong, narrow, 

 outer, and a broad^ but weaker, iauer branch*, the two 

 being separated by a narrow apterion. The outer branch 

 passes into the pt. fern oralis, sending at the same time 

 sharply forward a narrow double row of feathers to join the 

 hypopteron. The inner tract is probably continued down 

 to the anus, but the bird having been eviscerated, this region 

 was too much disturbed to afford trustworthy data. 



PL fern or alls (PI. I., PL II., P/./.).— This is a very 

 strongly developed tract of long, thick-shafted feathers. 

 It is not continued posteriorly beyond a point corre- 

 sponding to the free end of the pubis. From the anterior 

 margin is given off a comparatively broad branch to join the 

 pt. spinalis, from which it is otherwise separated by a broad 

 apterion f. 



Pt. cruralis (PI. I., PI. II., Pt.cr.). — This tract is con- 

 fluent above with that of the pt. femoralis ; the feathers 

 composing it are of a weaker texture than those of the 

 pt. femoralis and sparsely distributed. 



Pt. humeralis (PL II., Pt.h.). — Tapers to a point pos- 

 teriorly; in front is confluent with the short upper branch 

 of the pt. colli lateralis. 



Pt. alaris: — 



Metacarpo-digital remiges or primaries. — These 

 are 10 in number. The tenth is relatively long, and, like all 

 the other primaries, is much curved and sharp-pointed. The 

 sixth remex is the longest. All are longer than the cubitals, 

 to be described below, giving the outstretched wing a deeply 

 indented outline. 



Cubital remiges or secondaries. — Some 20 in number. 



* The "strength" or "weakness" of a tract is a purely arbitrary 

 distinction, depending upon the relative size and development of its com- 

 ponent feathers. 



\ See Apt. truHci lateralis, p. 6. 



b2 



