294 MR. W. K. PARKER ON THE OSTEOLOGY OF BALANICEPS REX. 
margin of these passages, formed by the nasal, is rough, and their bony roof about a 
line thick ; the lower, formed partly by the same bone, is smoother, but strongly grooved 
by vessels ; whilst the posterior boundary of the fossa is curiously scooped, the upper 
scooped concavity being small, and the lower large, and reaching to within one-third 
of an inch of the orbit. The actual nasal passage is less than half an inch long, and 
one-sixth of an inch broad ; but the grooved and scooped parts of the osseous boundary 
beneath project both behind and in front of it, so as to make its vestibular part full 
an inch long. The nasal. fossee and passages in Cancroma are very similar to these 
structures in the Baleniceps, save that they are relatively larger, and the surrounding 
parts composed of thinner and smoother bone. In the Heron, the nasal passages, which 
freely open into each other, are actually longer than in the Baleniceps; and in the 
Adjutant they are not so wide, but are twice as long. 
The large, well-made nostrils in Baleniceps have no affinity with those of the Pele- 
caninz, which are extremely small, and actually become obsolete in the adult of some 
species, e. g. the Cormorant. 
Pre-mawilla. (Pl. LXV. figs. 1, 6, & 7, pmz.) 
Fishes are curiously like birds in the condition of their proper maxillary bones, the 
‘ossa mystacea,’ which were not for some time recognized as the true homologues of 
the mammalian and reptilian maxillaries. In most typical fishes they are above and 
behind the dentary margin of the inter-maxillaries, and are themselves edentulous,— 
the exceptions being in the Salmonide, Sudis, &c. Passing from the study of any ordi- 
nary mammal, or from the Chelonia or Crocodilia to Baleniceps, it would seem at first 
blush difficult to put down nine-tenths of the huge face of the latter to the pre-maxillary 
elements ; yet such is apparently the fact. Nor is this bird exceptional, for in all the 
Gallinz the maxillary bones are, as in most typical fishes, above and behind the dentary 
margin ; and they are relatively small in all typical birds. We have, however, as in 
the class of Fishes, some instructive exceptions. In the Rhea, a bird whose nasals meet 
at the mid-line, and in which the sacrum is, much of it, as abortively developed as in 
the Frog, the maxillaries form half the region of the ‘ hard palate’ and one-third of the 
dentary margin. In the Emeu (Dromaius ater) a similar state of things exists, save 
that the premaxillary sends a long posterior, angular process, which hides the large 
maxillary laterally. The rest of the Struthionide are more or less like the Rhea and 
the Emeu in this respect. We have also a similar state of things in the smaller genera 
of the Fissirostres, as may be seen in the Common Goatsucker (Caprimulgus europeus) 
if examined when quite young. In this bird two-thirds of the palatal region and one- 
third of the dentary margin are formed by the superior maxillary bone. In the Duck, 
about half of the margin is mazillary. 
It was thought necessary to premise these remarks before passing on to describe the 
rest of the Baleniceps’ face. Certainly a large amount of territory has this same pre- 
