629 
Birds of Southern Cameroon. 
are equally long and abundant, the part of the spinal tract 
behind it is unbroken, bearing contour-feathers which take 
their places in the midst of those springing from the 
saddle. 
(3) Branching End of the Spinal Tract in the Pycnonotidse. 
In most Passerine birds the spinal feather-tract is only 
gradually and slightly widened at its hinder end, just in 
front of the oil-gland. In all Pycnonotidse which I have 
Text-fig. 21. 
B C 
A. Portion of the spinal feather-tract of Pycnonotus gabonensis. B. Spinal 
feather-tract of Ploceus nigerrimus. C. Spinal feather-tract of 
Calamocichla rufescens. (See Appendix, pp. 627, 628.) 
examined, the hinder end of the spinal tract extends laterally 
into a pair of short branches, one on each side, together 
forming a short transverse band. The feathers composing 
these branches are all very short, most of them being merely 
semiplumes; but some that stand nearest to the main 
tract are long enough, in some birds, to reach the light, 
thus being contour-feathers. 
These lateral branches were very marked in all specimens 
SJElt. ix.— vol. v. 2 u 
