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connective tissue until it was Joined by the dorsal end of the efferent 
pseudobranchial artery; its further course not being traced. 
In the two other specimens that were examined, the posterior 
portion of the pituitary fossa was constricted by an encroaching 
ingrowth, on either side, of the cartilage of the cranial wall, the 
cartilaginous dorsal edge of the conical pit that leads to the pituitary 
foramen being extended mesially to the level of the carotid foramen, 
and the corresponding part of the carotid artery bemg entirely en- 
closed in cartilage; this cartilage being simply a chondrified portion 
of the tough connective tissues that, in the two specimens first des- 
cribed, filled this part of the fossa. The carotid artery here traversed 
its foramen, which was exposed at the mesial edge of the ingrowth 
of cartilage, then formed the loop that I have described in an earlier 
work (1911), by turning mesially, posteriorly, laterally and finally 
antero-laterally, and then traversed a short canal in the side wall of 
the fossa before being jomed by the efferent pseudobranchial artery. 
Still another and quite different condition of this posterior por- 
tion of the pituitary fossa is described by Goopry in the specimen 
examined by him, for that author says of the pituitary canal, called by 
him the interorbital sinus: “‘On the inside of the skull, it is divided by 
means of a thin, outwardly directed cartilaginous bridge. The inter- 
orbital sinus passes posterior to this, whilst the cavity anterior to it 
forms the pituitary fossa. The foramen of the internal carotid artery 
is a small aperture lying in the floor of the skull immediately anterior 
to the pituitary fossa.’’ No such condition as here described was 
found by me im any of the specimens that I examined, and it is evi- 
dent that the pituitary fossa as described by Goopry is but a very 
small portion of the entire fossa as I have described it. It is further- 
more quite certain that the foramina called by Goopry, in his fi- 
gure 2, the foramina IIT and IV are, respectively, the foramina for 
the efferent pseudobranchial artery and the nervus oculomotorius. 
The posterior wall of the pituitary fossa lies in a nearly vertical 
position, but as the floor of the fossa inclines slightly postero-ven- 
trally the hind wall overhangs slightly the hind end of the fossa. 
The top of the wall forms a well rounded angle with the floor of the 
postpituitary portion of the cranial cavity, a transverse postclinoid 
wall thus being formed which is the evident homologue of some part 
of the crista sellaris, or dorsum sellae of higher vertebrates. The 
notochord, having traversed the cartilage of the basis cranii to a point 
