Wilder.] 5ob I July 15, 



from near the mesou dorso-laterad so as to cut the Tnedieornu (mcu.) and 

 Jiypoenmpa {hmp.) at about the middle of their length. On the left side, 

 the L. temporalis was allowed to fall somewhat by its own weight so as to 

 expose the fornix more fully. 



The velum and all the plexus were removed so as to display the peculiar 

 markings of the fornix and its mesal portion which is supposed to repre- 

 sent the lyra {ly.). 



The portas, (p.) appear both shorter and narrower than they really arc, on 

 account of the obliquity of their planes to the line of vision. The 

 V-shaped line called ?-jpa (jp-') which connects the two portse, separates the 

 delta, (dlt.) or entocoelian part of the fornix from the remaining surface, 

 which is wholly outside of the coelian cavity. The delta forms the roof of 

 the aula, the cephalic continuation of the diacoelia between the two portte, 

 and the ripa is the line of reflection of the endyma upon the two aiili- 

 •plexus ; the removal of these plexuses causes the rupture of the endyma 

 along the ripa. 



At each side, the ripa curves dorsad somewhat sharply so as to reach the 

 dorsal end of the porta ; at this point, and dorso-caudad for the entire 

 length of the rima (r.), the endyma is simply reflected from the contiguous 

 surfaces of the fimbria {fmh. ) and the corresponding border of the striatum. 

 Hence the rima is virtually closed, and thus wholly distinct from the porta. 



On the meson, between the portse, is seen the crista {crs.f.), which is 

 unusually rounded in this preparation. The carina, which sometimes 

 appears as a slight mesal ridge extending dorso-caudad from the crista, 

 does not appear in this preparation. The Recessus aulce {R. a. ) is the cleft 

 between the two Columns fornicis (Clm. f.) whose cut ends are seen just 

 caudad of the pr^ecommissura. The shading on the caudal aspect of the 

 columufe indicates, but rather too distinctly, a slightly depi'essed area, of 

 which the dorsal part, close to the crista, sometimes presents the appear- 

 ance of a transverse band, for which I suggest the name Gommisswra for- 

 nicis {Cs. f.). 



After a prolonged examination of many preparations, I am unable to de- 

 fine accurately the limits of the fornix and the lyra (ly.). A comparison of 

 the accounts given in standard works with the appearances presented by 

 the limited materials at my disposal, leads me to doubt whether the rela- 

 tive extent of the two parts in the human brain is well determined. 



The fasciola (fsel.) is thick, and no part of it presents the denticulations 

 from which its more ventral portion, in man, is called "fascia dentata." 

 The peculiar curve of the hypocampa, medicornu and fasciola is well in- 

 dicated by the fact that the F. liypocampce (F. hmp.), which corresponds 

 nearly with them in direction, is visible in this preparation only at its two 

 ends, near the splenium [sp.), and near the tip of the LI. hypocampoe {LI. 

 hmp.). Between the fimbria and the fasciola is a depressed line which may 

 be called the Fissura fimhrice (F. fmb.). 



Fig. 15. — The dorsal aspect oi l\\Q procoilice, with i\\eir proplexus. From 

 prep. 465. Natural size. 



