240 MR. W. P. PYCRAFT ON THE MORPHOLOGY AND 
Fig. 5. 
SS 
I 
\ 
conjoined flexors digitorum is highly suggestive of a walking or climbing animal. 
It seems to be conceivable that the Ostrich branched off from the avian stem before 
the power of flight was perfectly established. 
“The biceps of Struthio arises from the spina coracoidea and is inserted on to the radius 
and ulna and the membrane between them. The extensor metacarpi radialis is single. 
The ectepicondylo-ulnaris is absent or fused with the extensor metacarpi ulnaris. The 
extensor digitorum conmunis supplies only the index. The two pronators form only 
one muscle. The flewor digitorum sublimis and profundus arise by a single head 
from the flexor condyle of the humerus. The two muscles immediately divide; the 
upper part (=sublimis) ends in two tendons, of which one is inserted on to (the) 
