ENDOCRANIAL ANATOMY OF OREODON 



277 



addition, there may be seen on both sides, but particularly on 

 the right, several strand-like markings extending in graceful 

 curves from the surface of the lateral olfactory tract to that of 

 the tuberculum olfactorium. These markings which strongly 

 recall the picture of this region in the highly macrosmatic brain 



Ro.ecf. /R'«- 



S. QIS., 



Figs. 1, 2, 3 and 4 Camera lucida drawing of natural endocranial cast of 

 Oreodon, Specimen I, left lateral, right lateral, dorsal and ventral views re- 

 spectively. For photographs see figures 27 to 30. Abbreviations: Aa.c, ridges 

 corresponding to middle cerebral arteries; yl.c.i., internal carotid artery ridges; 

 Ar.Pyr., caudal expansion of pyriform lobe; D.c, depression for lodgment of 

 posterior clinoid processes; F.rhin.p., posterior rhinal fissure; For.lac.ant., 

 broken surface corresponding to anterior lacerated foramen; For.ov., broken 

 surface corresponding to foramen ovale; Fos.pit., eminence corresponding to 

 pituitar}' fossa; G.I., gyrus lunaris of Retzius; P.a.ect., processus acuminis ecto- 

 sylvii; R.d.s., ramus descendens suprasylvii; R.ect.ant., ramus anterior ecto- 

 sylvii; R.l.s., ramus lateralis suprasylvii; S.ans., ansate sulcus; S.cor., coronal 

 sulcus; S.lat., lateral sulcus; S.prs., presylvian sulcus; S.ss., suprasylvian sulcus; 

 Sin.i.lat., infero-lateral sinus; Sin. sag., sagittal sinus; T.o., tuberculum olfac- 

 torium; Tr.h.tub., tractus bulbo-tuberculare; Tr.o.l., lateral olfactory tract; 

 Tr.o.m., medial olfactory tract; II, chiasma ridge. 



