242 MR. W. P. PYCRAFT ON THE MORPHOLOGY AND 
In Apteryx the usual flexors and extensors of the forearm are present, and, as the 
late Prof. T. J. Parker points out, a rather unusually large development of muscles 
acting as pronators and supinators for so small and vestigial an organ. 
The biceps of Apterya is single-headed, arising only from the coracoid ; it is inserted 
only on to the radius. Apteryx differs only from the other genera in the possession of 
the Gallinaceous and Tinamine entepicondylo-ulnaris and an accessory brachialis 
anticus. 
In Casuarius and Dromeus the wing seems to have reached its most vestigial 
condition. 
The biceps in Casuarius arises only from the coracoid, and is inserted by a single 
tendon both upon the radius and ulna. In Dromeus, according to Beddard, the biceps 
has the same peculiar origin to that of Rhea (p. 241). 
“All the Struthious birds,” writes Beddard [7], “except Apteryx, have lost the 
serratus metapatagialis, the latissimus dorsi metapatagialis, and the pectoralis 
abdominalis. 
“On the other hand, Apterya has lost what the other Struthious birds have retained, 
the Jatissimus dorsi anterior and the rhomboideus profundus ; the latter muscle, 
however, is not distinguishable in the Cassowary. 
“It must be admitted, therefore, that Apteryx, so far as concerns the anterior 
extremity, has diverged from the hypothetical ancestral condition in slightly different 
lines from other Struthiones.” 
The rhomboideus superficialis in Rhea and Struthio arises as in Neognathe. In 
Rhea it is inserted on to both the coracoid and scapula, in Struthio on to the scapula 
only. 
In Apterya, Casuarius, and Dromeus it arises from the ribs. 
The rhomboideus profundus in Caswarius and Dromeus arises from the ribs. In 
Casuarius it is with difficulty distinguishable from the serratus profundus, and on this 
account Fiirbringer [22] inclines to disallow its existence as a separate muscle. 
The serratus superficialis of Apterya retains the pars metapagialis, which is wanting 
in the other Palwognathe. 
The coraco-brachialis internus of Casuarius, is entirely tendinous; in Rhea largely so. 
Furthermore, in this last genus it extends on to the sternum. In Struthio it is larger 
than in any other Palwognathe. 
THIGH- AND LEG-MUSCLES. 
Struthio and Apteryx only have the leg-muscles complete, which make up the 
formula AB. XY +. 
In the Struthiones generally the accessory femoro-caudal (pars iliaca m. caud-ilio- 
femoralis) calls for special comment. In all save Apteryx it is characterized by -its 
