1881.] 
301 
[Jeffries. 
The President announced the death of Prof. Lewis H. Morgan 
a Corresponding Member, and spoke briefly of his well-known 
archaeological studies. 
i 
The following paper was read : 
ON THE CLAWS AND SPURS ON BIRDS’ WINGS. 
BY J. AMOEY JEFFEIES. 
There are some very simple points in the structure of birds 
about which much confusion exists, among which may be men- 
tioned the claws and spurs on their wings. The spurs, such as 
those on the spur-winged goose, the parra or the screamer, are 
well known to all English ornithologists, while the claw has 
almost entirely escaped their attention. German authors on the 
other hand often confound the spurs with the claws. 
The spur is a structure like the spur on the tarsus of many 
Phasianidae. It consists of a bony core, on the anterior side 
of the arm, surrounded with connective tissue and covered with 
a thick horny coat. The development of the wing spurs I have 
not been able to work out, as no bird provided with spurs breeds in 
this vicinity. Wing spurs, however, resemble tarsal spurs so 
much that their development is probably the same. So the devel- 
opment of tarsal spurs, of which the domestic cock furnishes a 
good example, is not without interest. The tarsal spur is devel- 
oped, so far as the epiderm is concerned, in the following way. 
The first external sign is a slightly convex circular plate on the 
inner side of the tarsus. This is of the same histological structure 
as the surrounding scales, but does not form a fold pointing to 
the end of the limb, as in the case of the latter. The surface is 
covered by a thin “ epitrichial ” layer of large, flat, polygonal cells 
more or less granular, with inconspicuous nuclei. These cells are 
not readily stained by most reagents and so have often escaped 
detection. Below this layer comes, according to Kerbert, during 
the latter part of incubation, another layer of flat polygonal cells 
smaller than those of the outer layer. Of the existence of this 
layer I am by no means convinced, as it has only been seen on 
scales when looking from above, when it is perfectly possible to 
