SHi'FEi.Dr : OsrKoi.ocv of riii: 1 Ikkohion-ks. 16'.) 



The ollactory foramen of the Yellow-Crowned Night Heron is ex- 

 ceedingly small, while in the specimen before me the groove for the 

 passage of the nerve from it is single. The optic foramen, likewise, 

 unites with the interorbital vacuity in Nyciicorax. 



The posterior orbital wall in the Blue Heron looks forwards, down- 

 wards and slightly upwards ; it presents nothing of particular interest ; 

 \\\G. foramrn ovale which pierces this wall at its lower part in many birds, 

 has in the Herons moved round so as to appear on direct lateral view, 

 just over the upper edge of the (]uadrate. Upon this aspect the dome 

 of the parietal eminence is well seen in ])rofile as is the crotaphyte 

 fossa, with the muscular depression behind it. 



All Herons present three processes for our examination on the side 

 of the skull, these are, first, the squamosal process seen immediately 

 above and rather in front of the head of the articulated quadrate ; 

 second, the sphenotic process defining the boundary of the crotaphyte 

 valley above, and finally, another process just beyond the last, formed 

 at the union of the outer angles of the frontal and squamosal bones. 



Sutural traces among the bones composing the intraorbital l)ar have 

 almost entirely disappeared ; they can be made out only after careful 

 scrutiny in my specimen of the Snowy Heron, which, as I have said, 

 is not a fully grown bird. In the Blue Heron the line of union be- 

 tween the jugal and quadrato-jugal can sometimes be faintly recognized 

 in the adult individual. This posterior third of the bar is broad and 

 laterally compressed, and the articulation with the quadrate a substan- 

 tial one, by the usual cup and process joint. The jugal division of the 

 bone is more slender, though also laterally compressed, and the ante- 

 rior end of the maxillary portion, whose relation is to be described be- 

 low, is horizontally flattened, though not very broad. 



Several years ago Professor Parker found a " post maxillary " in the 

 Emu, and subsequently discovered a similar segment in several of the 

 Herons, as Ardea i^^arzetta, Nycticorax ardeola, and in the Jiitterns, as 

 Botaurus viridis and B. stellaris. 



This post maxillary is said to be situated or found behind the angle 

 , of the maxillary. I find no such bone in the specimens of Herons be- 

 fore me, and can add nothing to the statements of Professor Parker given 

 above. It may be that the post maxillary is j)resent in Ardea herodias 

 but so far absorbed in the adult as not to be recognized, or if a free 

 bone, it has undoubtedly been lost, as my specimens have been in my 

 collection for several years. In either case, fresh material in the flesh. 



