Osteological Studies of the 'Subfamily A rdeince. 
29 
they are generally overlaid with compact osseous tissue, and can¬ 
cellous internally. 
8 . Vomer is a single plate ; deep, sharp and produced in 
front; doubly carinate above, with the two carinations curled over 
outwardly so as to create a longitudinal trough upon that aspect; 
united with palatines behind and free anteriorly. Interiorly it 
shows its original bifurcatory form, with greater or less distinct¬ 
ness. 
9. Palatines are doubly carinated longitudinally ; inner keels 
being in close contact on the halves towards the rostrum (a con¬ 
tact that may be true anchylosis in very old individuals). Ante¬ 
riorly they are horizontally flattened and merge with the premax¬ 
illary and surrounding bones. The posterior angles of their outer 
carinations bluntly pointed an^not prominently produced. Ptc 
rygoidal 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 fa¬ 
cets for the mandibular articulation. 
13. A lacrymal bone is very large, and articulates with both 
nasal and frontal of its own side. I11 A? r dca its infero-produced 
portion is roughly parallel to the maxillary below it. In Nycli- 
corax it makes a wide angle with the same bone, the anterior end 
of its infero-produced portion being much elevated. 
14. Inter-orbital septum shows one large vacuity which in¬ 
cludes the optic and other small nerve foramina near it. In Ardea 
the foramen for first pair of nerves, generally very large. In Nyc- 
ticorax n. ncevius these are smaller. In Nycticorax violaceus (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 sep¬ 
arated by a considerable longitudinal median line . In N. violaceus 
it is by a tract of some width. 
17. Foramen ovale, lateral. 
18. In Ardea mandibular angle obliquely truncated. In Nyc¬ 
ticorax mandibular angle vertically truncated (least obliquely in 
A. virescens , least vertically in N. n. ncevius ). As a negative 
character we find the mandible in all Ardeince without a ramal 
vacuity. 
