PHYLOGENY OF THE PALZOGNATHA AND NEOGNATH 2A. 239 
a the Crypturi we have a second modification (fig. 5B, p. 240). The post-axial fleshy 
moiety has here apparently degenerated so as to be represented only by the vestigial 
zamsenilar slips from the body of the pre-axial portion, which is thick and fleshy. ‘The 
vinculum elasticum represented in Rhea by a rudiment only—by rudimentary I mean 
nascent, not vestigial—is here increased to form a great tendinous sheet. We may 
suppose that this is an improvement on the proto-carinate form seen in Rhea. 
In Opisthocomus (fig. 5c, p.241) both pre- and post-axial moieties are fleshy. The post- 
axial shows the first indication of the complex winculwm elasticum of the Neognathe. 
In Leptoptilus the pre-axial portion is almost entirely tendinous. Proximally, the 
tendon divides, one branch running directly to the ulnare, and one fusing with the 
anterior border of a muscular post-axial portion throughout the greater part of its 
length, finally trending upwards to join the main pre-axial tendon on the ulnare. 
This last, muscular, post-axial portion apparently represents the broad strap-shaped 
portion of Rhea ; it differs therefrom only in that it is inserted into the first cubital 
instead of the first metacarpal remex. 
There are numerous other modifications, varying in complexity, to be found amongst 
the Neognathw, a study of which would probably yield important results. 
The wing of Rhea represents, probably, as Dr. Gadow—to whom I showed these 
facts—remarks, a proto-carinate form. 
In the manus of Rhea, Mr. Beddard writes, ‘‘ we have more evidence of degeneration 
than in Struthio. ‘There are, in the first place, only twenty-one muscles at most, and 
some of these are much simplified. 
“The muscles that appear to be totally wanting are (1) the eatensor digitorum 
communis, (2) the pronator profundus. 
“The eatensor indicis is only represented by the belly arising from the wrist. ‘The 
flexor sublimis may possibly be represented by a slip of muscle arising from the 
tendinous edge of the flewor metacarpi uluaris... . 
“The origin of the biceps is peculiar; it arises not only from the coracoid spine by 
a rounded tendon, but also by a sheet of tendon edged with muscle from the whole of 
the coracoid and from just an adjacent bit of the sternum. It is inserted on to both 
radius and ulna. 
“ As in the Ostrich, the radio-metacarpalis ventralis arises from the ulna. In Rhea 
there is a special peculiarity in the presence of a muscular slip running from the 
tendon of the extensor metacarpi ulnaris near to its insertion to the extensor indicis. 
Finally the ectepicondylo-ulnaris is distinct.” 
Of Struthio, Mr. Beddard writes that, “in spite of the small size of the manus. . 
relatively to that of flying birds, there is but little, if any, evidence of degeneration in 
its musculature. On the contrary, indeed, for it might be said that the wing-mnscles 
of Struthio are less degenerate, or at any rate less modified, than those of Curinates, in 
that amount of muscle compared with tendon is greater. The complication of the 
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