Snui'Ki.nr : Osteology of thk HnkoiiiONES. 211 



bony union. In some specimens they may come, in contact with 

 each other mesially, or they may have the anterior part of the 

 vomer resting upon their hinder ends. In Aniea they are nearly 

 all of a bony spongy tissue (cancellous). In Nycticorax they are 

 generally overlaid with compact osseous tissue, and cancellous inter- 

 nally. 



8. Vomer is a single plate ; deep, sharp and produced in front ; 

 doubly carinate above, with the two cari nations curled over outwardly 

 so as to create a longitudinal trough upon that aspect : united with 

 palatines behind and free anteriorly. Inferiorly it shows its original 

 bifurcated form, with greater or less distinctness. 



9. Palatines are doubly carinated longitudinally ; inner keels being 

 in close contact on the halves towards the rostrum (a contact that may 

 result in anchylosis in very old individuals). Anteriorly they are hori- 

 zontally flattened and merge with the premaxillary and surrounding 

 bones. The posterior angles of their outer carinations bluntly pointed 

 and not prominently produced. Pterygoidal heads extensively in 

 contact, and above unite to form a groove for the rostrum. 



10. A post-maxillary present (?). 



11. Basi -pterygoid processes absent (negative character). 



12. Quadrates very large ; the foot of either having four facets for 

 the mandibular articulation. 



13. A lacrymal bone is very large and articulates with both nasal 

 and frontal of its own side. In Ardca its infero-produced portion is 

 roughly parallel to the maxillary below it. In Nycticorax it makes a 

 wide angle with the same bone, the anterior end of its infero-produced 

 portion being much elevated. 



14. Interorbital sci)tum shows one large vacuity which includes the 

 optic and other small nerve foramina near it. In Aiuha the foramen 

 for first pair of nerves, generally very large. In Nycticorax n. ucevius 

 these are smaller. In Nycticorax vio/acei/s (adult) they are very small 

 indeed, and just allow the passage of the nerve. 



15. Three jutting processes on lateral aspect of cranium. 



16. In Ardea and N. n. ncevius the crotaphyte fossae are separated 

 by a considerable longitudinal median line. In N. violaceus it is by 

 a tract of some width. 



17. i'oramen ovale, lateral. 



18. In Ardea mandibular angle obliquely truncated. In Nycticorax 

 mandibular angle vertically truncated (least obliquely in A. virescens. 



