PHYLOGENY OF THE PALJiOGNATHJ? AND NEOGNATH.E. 



241 



Pig. 5. 

 C. 



jZ.c.u. 



is. a. 



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 flexor carpi ulnaris. Note the large, fleshy inferior 

 portion eventually inserted into the base of the 1st primary remex and the tbin 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 Opistliocomus cristatus, showing another phase in the develop- 

 ment of the vinculum elasticum, and the persistence of a strongly developed posterior belly to the flexor 

 carpi ulnaris. Numerous intermediate stages occur amongst the Neognatha?. 



exp.sec. = expansor secundariorum. 

 fl.c.u. = flexor carpi ulnaris : ' = anterior, " = posterior portion. 

 uln. = ulnare. 

 v.e. = vinculum 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 flexor metacarjn 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-tdnaris. The additional muscle is a small pronator quadratus." 



