4d4 THE VOYAGE OF H.M.S. CHALLENGER. 
Its nature and relations in the group have subsequently been more extensively investi- 
gated by Reinhardt (vide supra, p. 8), who ealls it the “os crochu.” 
When best developed, as in the Albatrosses, the “ ossiculum lacrymo-palatinum ” is : 
small styliform ossicle of nearly cylindrical (as in Thalassiarche culminata, Pl. VI. fig. 7) 
or somewhat lamellar (Phebetria fuliginosa, Pl. VI. fig. 8) shape, attached above by 
an articulation to the inner face of the descending limb of the lachrymal bone, and below 
connected by a ligament to the upper surface of the palatine bone. Seen from the 
side, in the dried skull (wide Pl. VI. fig. 1) the bone is visible below the malar arch. 
It lies, in the recent state, in a cavity between the nose and the roof of the mouth, 
in an oblique position, pointing downwards and inward. This bone is present in all 
the genera and species of Albatrosses examined by me, as well as in Thalassiarche 
chlororhyncha, as mentioned by Reinhardt. In the Oceanitide, in Procellaria and 
Cymochorea, as well as in Daption and Pagodroma, its place is taken by a narrow 
ligament in which there is no ossification at all. In Bulweria, Pelecanoides, Fulmarus, 
Thalasseca, and Ossifrage there is a similar ligament, with a small, more or less ossified 
nodule of bone lying in it, only connected by connective tissue with the surrounding 
bones. In Aeipetes, Prion, Puffinus, Majaqueus, Adamastor, and istrelata it is small 
and delicate, articulating with the lachrymal above, and ending freely (in the cleaned 
skull) below. 
It is interesting to observe that a very similar bone, both as regards shape and 
position, occurs in the genus Fregata as already pointed out by Reinhardt, whose 
observation I have been able to verify. But it also occurs in forms so different from 
these as the Musophagide, many Cuculidee, Chunga and Cariama, as well as in some 
Laridze and Alcidee, so that its presence is obviously of no particular taxonomic value. 
Professor Parker informs me that its precise morphological significance is at present 
rather uncertain. 
The palate (vide Pl. VI. figs. 2 and 4) is always more or less incomplete below, 
the fissure dividing it being, by the less degree of inward development of the maxillary 
processes of the premaxille, and of approximation of the inward edges of the maxillo- 
palatines and palatine bones, longer and wider in the smaller than in the larger 
forms. 
The maxillo-palatine processes are concavo-convex lamelli, extensively fenestrated, 
pointing backwards, and with their inner edges appearing but slightly internal to the 
palatine bones. They remain free from each other in the middle line, and are also 
unconnected by ossification with the vomer or nasal septum. Hence the Tubinares are 
in this point strictly schizognathous birds. But in the Albatrosses, where the maxillo- 
palatines are very large and nearly vertical in position, the space between their inner 
edges is very narrow, and just in front of them the decurved end of the vomer fills up 
the intervening chink, especially in Phabetria fuliginosa, where it is firmly fixed to, 
