SilUKKl.Dl" : OSTFOI.OGV OF THK 1 1 KkOI )1()NES. 



175 



Above, on either side, the sphenotic process can be seen, pointing 

 downwards, while below it the squamosal process juts out, and between 

 the two, the crotaphyte fossre pass to the lateral aspect of the skull. 



In Nycticorax the supraoccipital region is carried to a point above, 

 and is usually divided by a pronounced crest with rounded summit. 

 A far broader strip separates the crotaphyte fossoe from each other in 

 the median line. 



'I'he occipital condyle, although of the same shape, is relatively 

 much smaller, and finally the posterior orbital peripheries can be seen 

 peeping above the parietal domes, all these differences enumerated 

 giving to these two skulls, even when only casually compared from 

 this view, a very dissimilar look. 



In a number of minor details, principally referable to relative posi- 

 tion and form, the points for examination within the braincase present 

 certain differences between the Night Herons and the genus Ardea. 



All the essential characters in the skull of Nycticorax n. iicevius agree 

 with the corresponding ones in the skull of Ardea herodias, as they 



Fu;. 8. Right lateral view of the sternum of Ardea herodias. Natural size, and 

 same bone as shown in Figure 7. 



have been described above. The skull of the former, however, is 

 about one-fifth less in point of size than it is in the last named species. 

 (See Fig. 29. ) 



The vHifidihle of the Herons offers us a number of points of interest 

 for our investigation. 



