238 Mr. W. P. Pycraft on the 
up to serve D. III. 1V. This arrangement so far appears to 
be unique ; yet it has probably been derived from an earlier 
and more primitive condition, shared in common with the 
Swifts and Humming-birds, a possibility which is discussed 
on p. 250. I would remark here, however, that, in the 
Swifts, as in the Colies, though the two tendons appear to 
fuse after the ankle-joint is passed, they, in reality, still 
shew traces of their originally separate condition. And 
from this it is clear that in the Swifts the flexor longus 
hullucis serves digits I. and 1V., while II. and III. are served 
by the fl. perf. digitorum. This point is of no small interest 
and importance, as will be shown later (p. 252). 
With regard to the wing-muscles. The deltoides pro- 
patagialis has the brevis portion large, fleshy, and continued 
downwards to the level of the extensor carpi radialis before 
becoming tendinous, the tendon running obliquely backwards 
after the fashion seen in the Passerine wing, but quickly be- 
coming lost in the fascia of the forearm. The longus portion 
is given off unusually low down—from the middle of the 
belly of the brevis portion—and in the form of a slender 
muscular slip, which quickly gives place to tendon. The 
origin of this muscle is from the far end of the clavicle. 
Biceps brachialis—TYhis is thick and fleshy, arising from 
the acrocoracoid laterad of the articulation for the furcula, 
and joins the humerus by one broad sheet of tendon running 
obliquely from acrocoracoid to humerus. 
Biceps propatagialis.—Is represented by a short, thick, 
fleshy band or slip, a fact which is to be reckoned among the 
many peculiarities of the Colies. 
Deltoides major (text-fig. 16, p. 239).—These muscles seem 
to present a very unspecialized condition, the /ongus and brevis 
portions being confluent and extending the whole way down 
the humeral shaft. Pars longa arises in the form of a broad 
fleshy band from’ the clavicle, extending nearly half-way 
down the limb, and from the scapula immediately caudad 
of the glenoid cavity for the humerus. The drevis portion 
arises from the os humert scapulare and from the rim of 
humeral cotylus of the coracoid and scapula, and is attached 
along the whole preaxial border of the humeral shaft. 
