382 PEOF. T. JEFFEET PAEKEE ON THE CEANIAL OSTEOLOGY, 



The paroccipital processes (par.oc.p:) are large and prominent; in Binornis they are 

 comparatively flat, and their ventral edges are evenly curved and not greatly produced 

 downwards (Plate LXII. fig. 47) ; in Mesopteryx casuarina (fig. 51) they are very 

 convex backwards, and their ventral borders are produced into bluntly pointed 

 processes which extend downwards to the level of the mamillar tuberosities. Other 

 species show intermediate conditions (figs. 47-58). In Emeus the supraforaminal 

 ridge stops short at the base of the paroccipital process ; in most other species it is 

 continued on to its lower angle. 



Externally to the supraoccipital fossa there is frequently a foramen, usually 

 continued into a groove, for one of the cerebral veins. The line of junction between 

 the supra- and exoccipitals is probably situated mesiad of this foramen, but I have not 

 seen a skull in which those two bones are distinct ; the paroccipital process is no doubt 

 constituted entirely by the exoccipital. 



ii. The cranial roof. (Plate LVI. fig. 1 ; Plate LVII. fig. 5 ; Plate LVIII. fig. 12 ; 

 Plate LIX. fig. 17 ; Plate LX. fig. 20 ; Plate LXI. figs. 23-34.) 



The roof of the cranium is formed mainly by the parietals {pa.) and frontals {fr), 

 the coronal suture passing transversely about halfway between the posterior lambdoidal 

 ridge and a line drawn between the posterior margins of the postorbital processes 

 (figs. 5 & 12). It is usually evenly arched both from before backwards and from side 

 to side. The lateral curvature is least in Binornis (fig. 47), in which also, taking 

 the basitemporal platform as horizontal, the anterior or frontal region is considerably 

 deflected (fig. 35). In Mesopteryx casuarina (fig. 27), Mesopteryx, species a (fig. 30), 

 and Emeus, species y (fig. 34), the roof is swollen on each side of the middle line, 

 producing a double tumidity ; in the other species of Emeus (figs. 38, 42, & 46) 

 there are slight unpaired elevations in the anterior and posterior frontal regions, the 

 intervening portion being flat or depressed. The roof is continuous behind with the 

 occipital region and with its squamosal prominences, narrowed between the temporal 

 fossae, and immediately in front of these produced into the large postorbital processes 

 [post. orb pr.), which pass outwards and downwards, forming the posterior boundary of 

 the orbit and almost meeting the maxillo-jugal arch (figs. 3 & 7). In most cases the 

 postorbital process forms an even curve ; in Binornis and Fachyornis it is divisible 

 into horizontal and descending portions, the former gently inclined downwards, the 

 latter vertical. 



Anteriorly the postorbital process passes into the supraorbital ledge, which is itself 

 continued into a sWoxi preorbital process [pre.orb.pr.) formed by a part of the ankylosed 

 lacrymal (figs. 5, 7, & 8). The margin of the orbit thus constituted exhibits certain 

 well-marked diflerences in the various genera and species. In most cases the whole 

 orbital margin is evenly curved or slightly sinuous ; in Binornis the supraorbital ledge 

 is at right angles to the postorbital process (figs. 23 & 35) ; in Anomalopteryx the 

 postorbital angle thus formed is slightly obtuse (fig. 36). The doubtful crania referred 



