DEVELOPMENT OF JACANA 295 



main true of the embryo, except in regard to the weakness 

 of the himbar or femoral tracts. While it cannot be said 

 that all are very strong, portions are especially well devel- 

 oped and the sheaths are nearly as well marked and firm as 

 the rectrices. In this res])ect they approach the Columbine 

 type. 



Forbes goes on to say: "The same relationship is indi- 

 cated by the inner, or main, pectoral (sternal) tract, though 

 very narrow, consisting, at least at its commencement, of 

 two or three rows of feathers in the Parridae, as well as in 

 the Charadriidae ; whereas in the typical Rallidae, according 

 to Nitzsch, it issues from the branch as only a single row of 

 feathers." This is also true of the embryo. The fact that 

 the lower tracts all join and fuse together throughout the 

 lower ventral half of the body, though probably of ancestral 

 origin, strengthens the su imposition that the bird belongs to 

 the IJmicolae, as this condition is very nearly duplicated in 

 the woodcock. 



The first embryo shows eight rectrices developed, with 

 two outside papillae still to lengthen; the later stage shows 

 ten. They are divided into two groups, one on either side 

 of the medial line with the intervening space very wide 

 and including the long, blunt end of the uropygium. The 

 longest rectrices are central, and the shortest — mere buds 

 — outside. Both upper and under coverts are well developed 

 and are as long as the rectrices, the under ones, however, 

 being without pigment. The primaries and secondaries 

 show only as papillae, ten for each, while on the lu'opygial 

 gland there are traces of undeveloped feathers. 



An examination of the three-day chick shows that the 

 rectrices have moved together at the center so as to make 

 an unbroken line, though the outer feathers, as in the em- 

 bryo, are only half as long as the central. The upper co- 

 verts — of which there are now five pairs instead of four — 

 are the same length as the rectrices and so close to them that 



