THE ANATOMY OF BIRDS. — OSTEOLOGY. 171 



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, 

 jiroducing the familiar "pitted" appearance (fig. 63, at c). 



The Nasal Bones (figs. 62 ; 71, n) might have been described next after the frontals, as 

 tliey 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, inferior, 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 ca\nty, 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 Eatitfe. 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. o\os, holos, whole ; pis, 

 pivos, rhis, rhinos, nose; fig. 62 j. But in the Columhidce, and in a great many wading and 

 swimming birds, whose palates are cleft (schizognathous), the nasal bones are schizorhinal 

 ((TX'C'^, 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. Incryma, a tear ; from the relation of the human bone to the tear- 

 duct ; figs. 62; 63, «; 71, I) 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 ft'out outer corner of the 

 frontal, and consequently bounding the orbit anteriorly ; it may be variously twisted, crooked, 

 liooked, etc. 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-frontal process, as in fig. 63, u. 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 imcinatnm, or os lacrymo-palatinum, would appear to be a palatine bone 

 distinct from the lacrymal; it lias been observed in the Mimiphngides and many other pica- 

 rian birds, in Tackypetes and certain Procellariidce. The lacrymal bone seems to be the priu- 



