ANATOMY OF BIRDS 



233 



which it blends ; a very small epiotic centre (e;>), between the 

 prootic and supra-occipital ; and tlie anterior semicircular canal (asr;) 

 embedded in the latter. In Dr. Shufeldt's figure the otic elements 

 are merely noted diagrammatically. According to Huxlej-'s gener- 

 alisation, the epiotic is in special relation with the posterior semi- 



Fio. 70. — Ripe chick's 

 skull, longitudinal section, 

 viewed insuls, x 3 diameters; 

 after Parker, In the man- 

 dible are seen : ink, remains 

 of Meckelian rod ; d, dentary 

 bone ; sp, splenial : o, an- 

 gular ; .s!t, surangular ; ar, 

 articular ; iap, internal arti- 

 cular process ; pap, pos- 

 terior articular process. In 

 the skull : pn, the original 

 prenasal cartilage, upon 

 which is moulded the pre- 

 maxillary, jix, with its nasal 

 process, npo:, and dentary 

 process, dpx; sn, septo- 

 nasal cartilage, in which is 

 seen nti, nasal nerve ; ntb, 

 nasal turbinal ; the refer- 

 ence line crosses the cranio- 

 facial suture, the face parts 

 and cranial parts being 

 nearly separated here by 

 the nick seen in the ori- 

 ginal cartilaginous plate ; 

 eth, ethmoid ; ]x, perpen- 

 dicular plate of ethmoid, 

 which will spread nearly 

 throughout the dotted car- 

 tilaginous tract in which it 

 lies, to form nearly all the 

 interorbital sei)tum ; trans- 

 verse thickening (in some 

 birds) below the reference 

 line eth will form the pre- 

 frontal or orbitonasal sep- 

 tum ; iof, interorbital fora- 

 men ; ps, presphenoidal 

 region, just above which is 

 the orbitosphenoidal region ; 

 2, optic foramen ; as, ali- 

 sphenoid, with 5, foramen 

 for divisions of the 5th 

 (trifacial) nerve ; /, frontal ; 

 sq, squamosal ; p, parietal ; 

 so, superoccipital ; asc, an- 

 terior semicircular canal ; 

 sc, a sinus (venous canal) ; 

 ep, epiotic ; eo, exoccipital ; op, opisthotic ; po, prootic, with 7, meatus auditorius intemus, 

 for entrance of 7th nerve ; 8, foramen for vagus nerve ; ho, basioccipital ; ht, basitemporal ; ic, 

 canal (in original pituitary space, Fig. (36, ic) by which carotid artery enters brain cavity ; ap, 

 basipterygoid process ; ap to rbs, rostrum of the skull, being the parasphenoid bone under- 

 flooring the basisphenoid and future perpendicular plate of ethmoid. (The scaffolding of the 

 upper jaw not shown, excepting px, etc.) 



circular canal ; the prootic with the anterior vertical canal, between 

 which and the foramen ovale (5) for the lower divisions of the 

 trifacial nerve it lies. That part on which the inner foot of the 

 quadrate is implanted is i)ro6tic. Below the drooping eaves of the 

 squamosal, before the flaring wing of the exoccipital, and behind 

 the quadrate bone, is the always decided and considerable cavity of 



