290 MR. W. K. PARKER ON THE OSTEOLOGY OF BAL^NICEPS REX. 



The lacrymal (prefrontal of Dr. Melville) becomes confluent with the sphenoido- 

 frontal in many genera of birds, — e. g. Trochilus, Picus, Ramphastos, Buceros, Psittacus, 

 Columba, Hemipodius, Ciconia, Kecurvirostra, lAmosa, Numenius, Vanellus, Parra, 

 Apteryx, Anas, Anser, Pelecanus, Sula, Phalacrocorax, Gavia, Sterna, Larus, &c. 



In a large number of genera it articulates with both the sphenoido-frontals and 

 nasals or ethmoido-frontals ; the latter receiving about one-third of the internal margin 

 of the lacrymal, the former two-thirds. 



In many birds the lacrymal coalesces with the antorbital 'pterapophyses,' but articu- 

 lates with the sphenoido-frontal, — e. g. in the Thrush and Lark ; whilst in others it 

 articulates with the antorbital process, but becomes confluent with the sphenoido- 

 frontal, — e. g. in the Lapwing (Vanellus cristatus). 



In those birds which have the upper part of the nasals well developed, e. g. the Pigeons, 

 GaUinaceous Birds, and Ostriches {Struthio, Rhea, Dromaius, Casuarius), the lacrymal 

 articulates entirely, or nearly so, with the nasal or ethmoido-frontal ; also in the Divers 

 (Colymbus septentrionalia and glacialis) the small lacrymal is in the same way entirely 

 facial in position. The rarest condition of this bone is seen in certain large Australian 

 Goat-suckers, e. g. Podargus humeralis, and in Balaniceps, in which birds it is not only 

 altogether in front of the sphenoido-frontal, but also coalesces with the nasal above, 

 and with the maxillary below. In these instances its upper and posterior portion forms 

 the outer and anterior part of the great fronto-maxillary hinge, instead of being behind 

 that hinge, and assisting the coalesced sphenoido- or principal frontals in forming it, as 

 in Parrots, and indeed in most birds. 



In Cancroma the lacrymal is small, much smaller in proportion than in its congeners, 

 Ciconia, Leptoptilus, Ardea, Botaurus, and Balaniceps, and three-fourths of its articu- 

 lation is cranial, or rather supra-orbital. In Podargus the lacrymal does not appear 

 to extend down far, but bounds the orbit above and in front ; in Balceniceps, however, 

 it passes down to be articulated with the zygoma, and forms the whole of the anterior 

 crescentic margin of the orbit. The most concave part of this margin is at the upper 

 third : above that part the lacrymal is thick and rugous ; below it becomes sharp, 

 forming a very perfect anterior boundary to the enormously expanded orbits. Inside 

 and a little in front of this clear sharp posterior margin of the deep lacrymal of BalcB- 

 niceps, a thin plate of bone extends inwards to the extent of nearly four lines : in the 

 upper part of this lamina (which is convex in front and concave behind) there is a 

 large oval foramen, the upper border of which is three lines from the roof, and the lower 

 below the middle of the bone ; its shape is oval ; its length six lines, and its width three. 

 This is the proper opening of the lacrymal canal ; it is quite external to the nasal 

 fossae, which in the dry skull open widely into the orbit in Balmniceps. The width of 

 the lacrymal of Baleeniceps above cannot be clearly seen ; but for the lower two-thirds it 

 appears (by a series of vascular passages along a more or less imperfect vertical tract 

 of bone) to be about two lines. These marginal holes and grooves are on a plane with 



