158 ME. W. P. PYCEAET ON THE MOEPHOLOGT AND 



than those included in the general remarks on the arrangement of the coverts. There 

 are only two median coverts in the hand, and, as already hinted, one of these may 

 represent the carpal remex. 



T. minores. — There are 6 to 7 rows of minor coverts on the cubitus. They are 

 wanting in the manus. 



T. marginales. — A broad bare space separates these from the minor coverts. They 

 are arranged along the pre-axial border of the wing, in groups of 3, just as in some 

 Neognathoe. They are wanting in the hand. 



Ala spuria. — There are 5 thumb-quills, as in the Neognathoe. 



Parapteron and Hypopteron. — These humeral remiges are wanting in Rhea. 



The feathers along the pre-axial border of the humerus are of great length. 



The whole under surface of the wing is perfectly bare, a probably degenerate 

 character. 



Pt. caudce. — There are no rectrices. 



TJropygium. — Absent in adult (p. 159.) 



The Rhamphotheca, like that of Dromasus, is made up of three pieces, both in the 

 sheath of the upper and lower jaws. There is no trace of the denticulations found in 

 Dromceus, either in the adult, nestling, or embryo. The aperture of the nostrils, 

 which are pierced through the cere, is lateral. 



The Podotheca of Rhea amerieana (fig. 1 d), according to Dr. Gadow [25], resembles 

 that of R. darwini, and differs from that of R. macrorhyncha in that the whole of the 

 acrotarsium is clothed in large scutes, whilst in R. macrorhyncha these scutes are 

 confined to the distal extremity. The leg of this last thus resembles that of Casuarius 

 and Dromceus. R. darwinii is furthermore peculiar in that the feathering of the 

 tibio-tarsus is continued downwards on to the tarso-metatarsus for some distance. 

 It is interesting and significant to note, however, that a few feathers occur in this 

 region in the embryo of R. amerieana. Indeed, in this latter their extension may be 

 traced downwards to within a short distance of the toes, as will be seen in fig. 2, p. 155. 



The planta is' also invested by large scutes. In the f -grown nestling and adult 

 these are arranged in the form of a series of paired plates. In the nestling and ripe 

 embryo they form a series of single transverse scutes. Along the inner side of these 

 large scutes will be found a number of smaller, wedged in between the larger. These 

 apparently gradually increase in size, and thus give rise to the secondary arrangement 

 of paired plates. 



The claws of the toes are laterally compressed, and form a strong median dorsal 

 ridge or keel, not met with in other Palceognathce. This is most marked in the 

 outer and inner toes. 



