MR. W. K. PARKER ON THE OSTEOLOGY OF BALANICEPS REX. 275 
Baleniceps and Adjutant. There is only a general class-resemblance between this part 
of the Pelican’s skull and that of the Baleniceps. 
The occipital cincture in the Boat-bill (Cancroma) is intermediate between that of the 
Heron and the Baleniceps ; the crests marking its boundary are thicker, but not more 
distinct than in the Heron ; in Baleniceps these ridges are fainter, at least in the skull 
of this scarcely mature captive. 
Upper Cranial Surface. (Pl. LXV. fig. 6.) 
The upper surface of the skull in this strangely interesting bird is formed (as in the 
rest of its class) principally by the parietals (figs. 1 & 6, p) behind, and the principal 
frontals anteriorly. The lacrymals (figs. 1 & 6, 1) generally assist the principal or sphe- 
noido-frontals (figs. 1 & 6, fr) in front ; but in the Baleniceps and a few other birds 
these bones are facial, being anchylosed to the nasals (figs. 1 & 6, n), or ethmoido-frontals 
of Goodsir, and intermaxillaries. The parietal region is eked out laterally in all birds 
by the squamosals (Pl. LXV. figs. 1, 3, 6, & 7, sq)—the temporals of Cuvier, and the 
mastoids of Owen, but incontestably shown to be the homologues of the mammalian 
squamosals in the masterly Croonian Lecture of Professor Huxley, p. 13. 
The only birds having a broad, flat, smooth cranial surface at all comparable to that 
of the Balzniceps are the Maccaws (Ara) ; although some of the Totipalmatz make some 
approach to it, e. g. the Pelican and the Gannet. 
In Cancroma the distance between the orbits is proportionally much less, and the 
general surface, although smooth, is more irregular, whilst in the Adjutant it is convex 
and rough. In the Heron, the upper part of the skull is as polished and smooth as that 
of the Baleniceps ; but its shape is very different, its length being very great in propor- 
tion to its breadth. The relative proportions of the upper part of the Balzniceps will 
be best shown by a few comparative measurements, the width and length being taken 
at the following points. 
Measurements of Crania. 
First measurement,—across the cranio-facial hinge. 
Second measurement,—across the middle of the orbital margins. 
Third measurement,—across the post-frontal processes. 
Fourth measurement,—entire sagittal line of the skull proper. 
First Second Third Fourth 
measurement. measurement. measurement. measurement. 
in. in. in. in. 
1. Adjutant, Leptoptilus . 2 23 34 33 
2. Whale-bird, Balenicepsrex . . . . 1Z 14. 344 z 
3. Boat-bill, Cancroma cochlearia $ 2 12 13 
4. Goatsucker, Podargus humeralis . 4 fy 1Z 13 
5. Grey Heron, Ardea cinerea cd a 13; 23 
6. Hornbill, Buceros bicornis . 23 23 21 23 
7. Maccaw, Ara ararauna 12 12 2 23 
8. Pelican, Pelecanus onocrotalus 12 12 23 2 
