

THE BOM-:s l.\ IU1W8. 115 



>x of tin minium. TllC holies \\llirli compo-e the cranium :irc. a.-i ill mammalia. 



ipitid. parietal, frontal, ethmoid, .sphenoid, and two teinpora's. These l*>nes are 



lated from each other, excepting during early life in th- shell; and tin- oni-itying 



-s whicli unites them is so rapid, tlmt the cninium, shortly after hutching, i.-< 



aln-a ly a .-ingle piece. No detailed description of tlie separate bones will bo given here, 



but only a few briet observations which may be of some utility. 



Tims, the fK-i-ifn'tnl bone shows for articulation with the siiine only a single cond\l.-, 

 i-itnated iiudi-r the oecipitnl foramen, and excavate 1 by a slight groove. In palmipedes, 

 this Ix.ne is pierced, behind the crests which give attachment to the ext< n^.r mn>c]. ,, 

 by twn foramina which p. n trate the cranium, and represent iKTinauent f./ntanella. 

 The fHiri'tnl bone is f< chly developed, and formed from only two primary nuclei. 

 The ji-i'iifiil is the lar^e-t bono of the cranium; its orbital process id supported 

 particular pietv which is generally considered as l>elonging to the large \\inu r 

 Of the sphenoid. The perpendicular lamina of the <tlmii<l is considerable, and 

 form-* bet\\t ( n the two orbits a thin vertieal teptum (fig. 73, 8). Its posterior border is 

 iiot.-hul opposite to the optic foramen, and thus constitutes an owning which com- 

 mnni'-at's between tin t\\o orbital cavities (fig. 73, 9). It is also channeled, near its 

 upjH r border, by a fissure which t rminates by two openings t its extremities, one 

 entering tlie cranium, the other the nasal eavities. This fissure and these foramina 

 permit tin- pa. a-c of tl.e ethmoidal nerve, which in this w:iy traverses tl e orbit before 

 arrivii ion. The etltiiuridal cells are more membranous than bony ; their 



base is attached to a v. i y delicate transverse plute, which is often membranous and not 

 crihbled. a id forms [art of the anterior orbital wall. These cells repla-e, at the same 

 time, the lateral ni;i.-.-. > of the ethmoid and turbina'ed bt.nes of mammalia. The 

 ffikenoid appears to be formed of a single piece, and shows on its sides two diarthrodial 

 -!>ndinir t > the pteryg.>ids. It is pierced by one foramen for the passage of 

 the optic nerves; but this foramen opens on the outer and opposite side of the posterior 

 iiot<-h of the interorbital septum, and thus allows eai-h of the nerves passing through it 

 to reach the eye for whirh i' was intended. 



It is worthy of remark, tint an analogous disposition is also noticed in the mbbit. 1 



The t> iu}*jr<il liones present at their base an articular surface correspi Hiding to the square 



In ih<' j'mrl sjxcie.s, tlie zygomatic process forms a small flattened tongue, 



din-.-t d forwiirds, tometimes free, and at other times united by iis superior border 



t tin- Mimmit of the orbital process. These two eminences are exceedingly short 



In i>'tlini/>icg they are consolidate I and confounded so intimately, that it 



.- impossible to distinguUh them from one another. From this union results u 



long and strong process, which inclines torward and meets a particular prolongation of 



iin^iiic, foiming with it amil bony arch. This arch limits, below auJ outwardly, 



;vity. 



* of tl,'- face. The superrmixilla c mprises: a premaxilla, two na&il, two 



lai'lnynnl. uv.i pal it--, two pterygoiil. two zygomatie bones, and a vomer. The inferior 



H for its base a maxillary b<ine, which articulates \\ith the cranium by means of 



ry pieces named the tquare bone*. The prennuriUary Itone is found. 



hing is completed, of two lateral pieces, whicli represent the two sinnl! 



premaxiihi! ies of mammals. This bone is very con.-ideiablc, rnd of itself forms the base 



of the np[M r beak, whoso form it detenu ine.-i; it is pointed ai.d conical in the gallinacea, 



and wiile and tl:itteiied a'xjvc iiini Ix-low in palmipedes. In front it circumscriU-* ihe 



external openings of the nose, and is prolonged superiorly int>> two lengthy processes 



which dovetail I" twi . n the nasal bones. Two inferior processes belonging also to this 



ncur in tlie formation of the (Ratine roof. The wperimuriUariet, analogues of 



.j-ermaxillaiies of mammals, are two rudimentary txmcs Bitunt- d on the sides und 



ut the base of the Ix-ak. They form a part of the palatine roof and the walls of the 



naoal ca\ :, - I he iuiml bone* circumflcribe alx>ve, inwardly, and even outwardly, the 



: there e.ivities. The jKilutr l*>nt* encircle, us in mammals, the guttural 



js of the no.se, and eon.-t.tnte in gr at p.irt the roof of the palate ; their j* sterior 



aiust the pteryg< id.-: the anterior joins the .-up rnmxillarie.s and the 



; "pro.-os ut' the preinaxillary Lone. The /</ r// ; /../i/ e\t. ml obi .jiiely fn.ni tho 



"phenoid to the square bone*, and are united to tl.e tfKeavAA by diarthroiiial urticulation. 



1 Thi.-. nnal< .uy is nally hti iking, and might, in our opinion, .-erve as a basis for 



a n< w determination of tin r.t- i.Tl.ital .-eptum. We are tempted, indeed, t n-ider 



ny lamina a> the in , riop .-pheiioid and the middle |H,rlioii of the ethmoid of bird-. 

 manner of \iein- it ten.l> toc..ntirm the ideas of M. Tal'iirin mi the inferior 

 sphenid and the ethmoid of maminnls. 



i 2 



