STRUTHIONES 497 



Though no rectrices can be distinguished, there are 

 recognisable remiges. PAEKER counted nine or ten cubitals 

 and two or three metacarpals and a single mid-digital ; there 

 are also tectrices majores. An extraordinary peculiarity of 

 Aptenjx is the situation of the nostrils near the very end of 

 the beak. 



Of Casiiarius there are some ten species which are found 

 in several of the islands lying to the north of the continent 

 of Australia, such as New Britain, Ceram, &c., as well as- 

 one species, Casuarius australis in the north of Australia 

 itself. They are remarkable externally for their black 

 coloration, brown in the young, and for the horny casque 

 upon the head. The neck is naked and adorned with 

 bright colours, in which blue is especially prominent, and 

 there are often dependent folds of bright-coloured skin in 

 this region. The feathers have an aftershaft as large as 

 the feather itself; the rectrices are unrecognisable, but the 

 remiges are present in the shape of long spines which corre- 

 spond to the stems of the feathers. The claw of the inner 

 of three toes is very elongate. 



The emu, Dronmus, 1 is entirely Australian in range, and 

 contains two species. This genus, agreeing with the casso- 

 wary in laying a green egg, has no helmet or wattle, or stiff 

 spines upon the wing. It has, however, like the cassowary, 

 a large aftershaft. 



The fourth genus of Struthiones is the South American 

 Rhca, of which three species are recognised. These have 

 been carefully compared by GADOW. 2 The genus is cha- 

 racterised, so far as external characters are concerned, by 

 the want of an aftershaft and by the feathered neck not 

 naked, as in the ostrich ; it lays a yellowish white egg. The 

 Rlica is three-toed. There is a distinct ventral apterion 

 running from sternal callosity to vent. 3 



1 G. DUCH.UIP, ' Observations sur 1'Anatomie clu Dromons? Ann. Sci. Nat. 

 (5), xvii. 1873. 



- ' On the Anatomical Differences in the Three Species of Rhca,' P. Z. ,S. 



->, p. 308. 



3 ' A. BOECKING, De Rhea Americana, Diss. Inaug. Bonn, 1863 ; J. F. 



K K 



