270 ME. W. P. PYCEAFT ON THE MOEPHOLOGY AND 



Apteryx. 



a. Vomer long, equal to or longer than the width across the paroccipital 



processes at widest, notched anteriorly, and with the median cleft not 



extending forwards beyond the middle A. australis. 



b. Vomer less than width across paroccipital processes. 



a'. Vomer notched anteriorly, the median anterior portion nearly as long as 

 the paired posterior limbs ; paroccipital processes well defined ; basi- 

 temporal plate bounded antero-laterally by a pair of ridges passing 



forwards into parasphenoidal rostrum .... A. haastii. 



b' . Vomer imperfect anteriorly, median portion much shorter than the paired 

 posterior limbs. 



a". Size not less than 7 inches A. a. mantelli. 



b" . Size not less than 65 inches .............. A. oweni. 



Rhea. 



A. Temporal fossa more or less sharply defined and extending backwards to 



meet the lambdoidal ridge; lachrymal with elongated dorsal processes 

 arching backwards over orbit. 



a. Posterior nares markedly wider anteriorly than posteriorly ; anterior vome- 



rine cleft not extending backwards to the level of the hinder angle of the 

 lachrymo-nasal fossa; length of quadrato-jugal fossa less than width 

 across beak measured across the maxillary pillars bounding the lachrymo- 

 nasal fossa anteriorly R. americana. 



b. Posterior nares not wider anteriorly than posteriorly; anterior vomerine 



cleft extending backwards to the level of the hinder angle of the lachrymo- 

 nasal fossa; length of quadrato-jugal fossa equal to width across beak at 

 the level of the maxillary processes bounding the lachrymo-nasal fossa. R. macrorhynchu l . 



B. Temporal fossa not sharply defined and not extending backwards to lambdoidal 



ridge; lachrymals with short orbital processes; anterior vomerine cleft very 



short R. darwini. 



Drom^us. 



a. Length not exceeding 7 inches. 



a'. Post-orbital processes short D.novce-hollandia. 



b'. Post- orbital processes long, extending downwards to within a short distance 



(^ in.) of quadrato-jugal bar . D. irroratus. 



b. Size not exceeding 5 inches; roof of skull with a very conspicuous cerebral 



dome D. ate)- 2 . 



1 The specific characters of this species have been drawn from a single adult skull, kindly lent me by 

 Mr. Beddard from the Zoological Society's Collection. 



2 This skull is from a skeleton in the Florence Museum. The bones of the palate are missing. The cranium 

 closely resembles that of D. novce-hollandice, differing therefrom chiefly on account of its very small size and 

 the prominence of the cerebral dome, whilst in the peculiar form of the inferior limbs of the lachrymal it 



