PHTLOriEXY OF THE PAL^OGNATH.E AND XEOGXATH^. 269 



process of iiiuuli'ate long, articulatiuf;- «itli wliok' inner l)ordcr witli 



pteiygoid ; olfactory cavity of great size Dinornithida. 



c. Vomer deficient postei'iorly, not extending l)ackwards to reach the pterygoid, 

 anteriorly extending forwards, as in Dronuvas, to conceal the parasphe- 

 noidal rostrum ; the body of vomer deeply hollowed, fitting closely on to 

 the rostrum, and embraced on either side by the maxiIlo-|)alatine pro- 

 cesses ; maxillo-palatiue processes hastate ; anterior jialatine processes of 

 great size; pterygoid laminate; palatine rod-sliaped, fu.sed proximally 

 with external border of pterygoid ; prcmaxilla wanting a palatine process ; 

 lachrymals continued backwards to fuse with a chain of supra-orbitals 

 and with the frontals, so as to enclose a suin-a-orbital foramen ; lachrymal 

 with an osiculum lachrymo-]mluti»um; nostrils holorhinal ; anterior narial 

 and lachrymo-nasal fossa confluent ; quadrate with long recurved 

 process bearing a well-defined projecting facet for the jiterygoid in 



the middle of its internal ventral border Strvthio. 



B. Beak elongated, dccurved, probe-shaped; anterior narial fossa minute, eon- 

 fined to tip of beak; lachrymo-nasal fossa cnoruious, extending forwards to 

 within a short distance of tip of beak ; skull rounded, without post-(n-bital 

 processes; lachrymal vestigial ; olfactory chamber of great size, extending 

 backwards to optic foramen ; vomer passing backwards to fuse with the 

 pterygoid and palatine, and, with these, helping to form the floor of a 

 tubular recess opening inwards Aptenjx. 



Key to the Species. 

 Struthio. 



a. Maxillo-palatine processes not rising dorsad, the anterior border of the 



maxillo-palatine process at right angles to the long axis of the skull, 

 a'. Palatines projecting distad beyond anterior border of maxillo-palatine 

 process ; maxillo-palatine processes without any external lateral fenes- 

 trated plate s. aust rails. 



b!. Palatines not reaching as far forward as the level of the anterior border of 

 the maxillo-palatine process. 

 a". Vomer very short ; parasphcnoidal rostrum thick ; maxillo-palatine 



processes with an external lateral fenestrated plate S.molybdophaue.i. 



b". Vomer very long ; maxillo-palatine processes without an external lateral 

 fenestrated plate ; parasphcnoidal rostrum slender ; roof of the skull 

 with deep ilepressions mesiad of the supra-orbital ledges ; nasals 

 meeting in the middle line proxiniad of the nasal process of prc- 

 niaxilla S.meridioua/is' . 



b. Maxillo-palatine processes rising dorsad ; anterior border of maxillo-palatine 



processes sloping obliquely backwards ; vomer broad, with short, pointed, 

 posterior limbs; palatines projecting distatl beyond maxillo-palatine pro- 

 cesses S. camelus. 



' We believe that Strutldo mas.iamis (^Noum.) is identical with this bird. — \V. K. & W. P. P. 



VOL. XV. — FART V. No. 21. — Dtcemher, 19UU. 2 p 



