THE ANATOMY OF BIRDS. — OSTEOLOGY. 165 
ramify beneath the horny integument; and in birds with very sensitive bills, as a snipe or 
duck, the end is perforated sieve-like with little holes,-into which the skin shrinks in drying, 
producing the familiar ‘‘ pitted” appearance (fig. 63, at c). 
The Nasal Bones (figs. 62; 71, ») might have been described next after the frontals, as 
they continue forward the general roofing of the skull; but are conveniently considered in the 
present connection, being in birds rather “facial” than “cranial.” They are of.large size in 
birds, and pronged, — one fork, the superior process, being applied for a variable distance along 
the outer side of the frontal process of the premaxillary, the other, wferior, descending to or 
towards the dentary border of the maxillary or premaxillary, or both ; the divergence of these 
two processes bounding the nostril behind. The base of the nasal, uppermost and posterior, 
anchyloses (usually) or sutures (often) or articulates (as in parrots) with the antero-external 
border of the frontal bone; its frequent collateral connections being with the lacrymal or 
ethmoid, or both of these. The nasals are very variable in shape, as well as in the extent 
of their connections. When expansive, they may wall in much of the nasal cavity, as well as 
bound the nostrils. These latter openings, as far as the bony boundaries are concerned, are 
usually much more extensive than they seem to be from the outside, being much contracted by 
membrane and integument. Ordinarily, each forms a great vacuity, which the descending 
prong of the nasal bone separates from a similar vacancy between itself and the lacrymal, the 
lacrymal in“turn interposing between this and the orbital cavity. The descending process of 
the nasal, in fact, is a marked object at the side of the base of the upper mandible of most birds, 
though slight or rudimentary in the Ratita. A character of the nasals has been employed in 
classification by Mr. Garrod. A bird having the bones as above generally described, with 
moderate forking, so that the angle of the fork, bounding the nostrils behind, does not reach so 
far back as the fronto-premaxillary suture, is termed holorhinal (Gr. édos, holos, whole ; pis, 
pwés, rhis, rhinos, nose; fig. 62). But in the Colwmbide, and in a great many wading and 
swimming birds, whose palates are cleft (schizognathous), the nasal bones are schizorhinal 
(cxife, schizo, I cut) ; that is, cleft to or beyond the ends of the premaxillaries ; such fission 
leaving the external descending process very distinct from the other, almost like a separate 
bone. Pigeons, gulls, plovers, cranes, auks, and other birds are thus split-nosed. The value 
of the character, except as an auxiliary, is doubtful. 
The Lacrymal (Lat. lacryma, a tear; from the relation of the human bone to the tear- 
duct ; figs. 62; 63, w; 71, 1) is one of several splint-like membrane-bones of the skull, having 
little intimacy of relation with the general morphology of the cranium, though quite constant in 
birds, and often very conspicuous. It is situated at or near the anterior outer corner of the 
orbit, near the nasal but behind that bone; sometimes anchylosed, sometimes very loosely 
attached, oftener firmly sutured with the frontal; and may also have connection with the nasal 
and ethmoid. It is generally a claw-like affair, depending from the front outer corner of the 
frontal, and consequently bounding the orbit anteriorly; it may be variously twisted, crooked, 
hooked, ete. It is singularly elongated and distorted in the ostrich. In the duck tribe, in 
which the lacrymo-frontal region of the skull is greatly elongated, the lacrymal has coex- 
tensive attachment to the frontal bone, and is broadly laminar, with a downward process ; 
in some ducks bounding at least a fourth of the orbital brim, and almost completing the circle 
by extending toward the very protrusive post-froutal process, as in fig. 63, «. In some parrots, 
the rim of the orbit is completed below, and even sends a bony bar to bridge over the temporal 
fossa behind the post-frontal. In some birds, the lacrymal is quite free, and even in more than 
one free piece. The os wncinatum, or os lacrymo-palatinum, would appear to be a palatine bone 
distinct from the lacrymal; it has been observed in the Musophagide and many other pica- 
rian birds, in Tachypetes and certain Procellariide. The lacrymal bone seems to be the prin- 
