PHYLOGENY OF THE PALAOGNATHZ AND NEOGNATHZ. 24] 
Fig. 5. 
C. 
Te OA 
N 
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A—Inner view of a dissection of the wing of Rhea americana, to show the remains of the expansor secund- 
ariorum and the ?proto-carinate condition of the flewor carpi ulnaris. Note the large, fleshy inferior 
portion eventually inserted into the base of the 1st primary remex and the thin tendinous band which 
runs along its free border, probably representing the vinculum elasticum. 
B.—Inner view of a dissection of the wing of Calodromas elegans. Note that the fleshy posterior portion of 
the flexor carpi ulnaris has become reduced to slender slips of muscle to the bases of the secondary 
remiges, whilst the vinculum elasticum has greatly increased in size to form a broad tendinous sheet. 
C.—Inner view of a dissection of the wing of Opisthocomus cristatus, showing another phase in the develop- 
ment of the vinculum elasticum and the persistence of a strongly developed posterior belly to the flewor 
carpi ulnaris. Numerous intermediate stages occur amongst the Neognathe. 
exp.sec. = eXpansor secundariorum. 
fl.c.u. = flexor carpi ulnaris : ‘anterior, ''=posterior portion. 
uln. = ulnare. 
v.e. = vineulum elasticum. 
radiale, the other fuses with the upper tendon of profundus, and also gives off two 
slips which surround that tendon and, reuniting, fuse with the lower tendon of the 
profundus. The lower part of the muscle (=profundus) gives off two tendons, of 
which the upper ends on the first metacarpal, while the lower runs to the base of the 
last phalanx of the index. 
“The fleor metacarpi ulnaris ends fleshily on the ulnare, but is prolonged beyond 
this bone, receiving also some fibres from it to the metacarpal. 
“The radio-metacarpalis ventralis . . . . arises from the ulna and not from the radius. 
“ The total number of muscles in the hand of the Ostrich is twenty-three, allowing for 
the absent ectepicondylo-uinaris. ‘The additional muscle is a small pronator quadratus.” 
