397 
C. J. Sundevall on the Wings of Birds. 
These different kinds of feathers are :— 
Upper (superiores), when seated upon the upper side of 
the wing, and 
Lower (inferiores) upon its lower surface ; and further from 
the different parts of the arm :■— 
Upper-arm feathers (humerales) on the humerus, 
Forearm feathers or merely arm-feathers (cubitales) on 
the cubitus, and 
Hand-feathers, “ Lash-feathers ” (Primores, L.), on the 
hand. 
Upon this terminology we shall have something more to 
say further on. It is only upon the cubitus that all the 
different kinds of wing-feathers occur together. 
The structure of the feathers need not here be described; 
it does not belong to our subject, and is treated in detail in 
NitzsclPs ' System der Pterylographie/ Nevertheless a 
terminology of their external structure may not be super¬ 
fluous in this place, which will give the opportunity of pro¬ 
posing some small changes in the terms employed by Nitzsch 
in the above-mentioned work, which he did not himself 
complete. 
The external parts of the feather are as follows :— 
1. Calamus (the quill-tube, fig. 12, a), the transparent, 
horny part, which is fixed in the skin. 
2. Rhachis (the shaft, h ), the part filled with white pith, 
which bears the vane. On the whole outer side (obverse side) 
this is clothed with a direct continuation of the calamus in 
the form of a sharply defined horny lamella. The whole of 
this side is somewhat convex or flat, without any depression, 
and scarcely elevated above the vane. The inner or opposite 
side is considerably elevated above the vane, covered with a 
peculiar, thinner, and sharply-defined horny lamella, and has 
a longitudinal impressed line which terminates in the 
Umbilicus [d), or the opening into the interior of the tube. 
This opening is very small, and is closed by a projecting 
point of the dried membranous parts remaining in the tube. 
Fig. 12 shows a small feather, seen from the reverse side. 
