. The Encyclopaedia Britannica; ... A dictionary of arts, sciences and general literature. y the frontals, lachrymals, nasals, andnasal processes of the premaxiUaries, in their the frontals diverge by narrowness in front,behind the nasal processes of the premaxiUaries, there theethmoid is seen becoming fast bony from the substance ofthe perpendicular plate, and not by a separate upper boue,as in the Struthionidae.^ As to the facial bones, they yetretain much distinctness, and the prenasal and Meckelianrods still linger. The articular end of the latter rod is nowossifying fast,
. The Encyclopaedia Britannica; ... A dictionary of arts, sciences and general literature. y the frontals, lachrymals, nasals, andnasal processes of the premaxiUaries, in their the frontals diverge by narrowness in front,behind the nasal processes of the premaxiUaries, there theethmoid is seen becoming fast bony from the substance ofthe perpendicular plate, and not by a separate upper boue,as in the Struthionidae.^ As to the facial bones, they yetretain much distinctness, and the prenasal and Meckelianrods still linger. The articular end of the latter rod is nowossifying fast, the two angular processes, so large in thistype, are now bony. The fast coalescing roof and thacoalesced floor are now of great thickness, and the diploein thia type is coarse {op. cit, plate 86, fig. 14). In allthese growing stages, tracing bone by bone, as it appears,we have not yet met with the presphenoid, nor seen the be-haviour of the great ethmoidal wall in relation to the hinderskulL In the most advanced winter chickens these thingsare to be seen (fig. 18, , , ) elk. —Skull of Younff /*o(r of first winter, nifith stage, side view. X IJdiameters, I and 2, the two small orbito-sphenoidal centres above thesmall preaplienold , which is only partially ossified at present. Theenturcs at this stage are very initnictive. Tlie fore-face has been removed,and the ant-erior edge of the perpendicular ethmoid () ifl the posteriorboundary of the cranio-facial cleft, f Phil. Trans., 1866, 8, fij. 10, eth., The presphenoidal region is merely that band of car-tilage which lies partly above, but mainly behind, thefenestra {). A small ossicle has appeared in it closebelow the second orbito-sphenoid {, 2), the foremostorbito-sphenoid { 1) has coalesced with the perpendicu-lar ethmoid. From that boue the rostrum (jf the parasphenoid isstill distinct {), but the perpendicular plate has nowreached the basi-sphenoid {, b
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