484 ON THE RELATIONS OF MAN WITIL THE LOWER ANIMALS 
stantia constat, que hoc loco neque latior est, neque alium colorem 
exhibet ac in quovis alio cerebri gyro. 
“Inter utrumque tuberis parietem spatium invenitur, quod vasculosa 
cerebri zque explet ac sulcum inter duos alios gyras in superficie 
cerebri sitas. 
“Si in superficie cerebri eo, qui eminentie isti opponitur loco 
membrana cerebri media et interior detrahitur, tuber illud evanescit, 
ut quamprimum cerebri superficies extenditur, in planum mutatur. 
“ Discrimen ergo, hoc tuber inter et processum cerebri lateralem in 
eo consistit, quod illud verum absolutum, gyris in exteriore cerebri 
superficie sitis omino simile, quoad interiorem vero structuram plane 
equale, in interiore cerebro sive in aliqua ventriculorum ejusdam parte 
existens gyrus sit; quod e contrario hippocampus, si cum gyris in 
superficie cerebri existentibus comparatur, tantummodo gyri alicujus 
pars, non autem absolutus atque integer gyrus sit, cujus initium in 
interiore cerebro, aut in aliqua ventriculorum parte enistit.” 
The brothers Wenzel figure in their excellent plates the various 
conditions of the posterior cornu and hippocampus minor to which 
they refer; and it is remarkable that the brain which they have 
selected as exemplifying the absence of the hippocampus minor on 
both sides, Tab. v., Fig. 1, is said to be “ex triginta annorum zthiope,” 
while the most remarkably developed hippocampus, Tab. vii, Fig. 3, 
is “ex septem annorum puero.” 
The work whence these extracts are taken is contained in the 
libraries both of the College of Surgeons and of the Royal Society ; 
but, even if it were inaccessible, a well-known and more modern writer 
fully bears out the doctrine it contains. I refer to Longet,! who 
states that, in the human brain, “ the posterior cornu is found of very 
different lengths and breadths. I have found brains in which it 
extended up to within a few millimetres of the surface of the posterior 
lobe, and others in which it ended at more than three centimetres 
therefrom.” 
The same excellent authority, in describing the posterior cornu of 
the lateral ventricle, says :— 
“Its inner and lower wall is raised by a convolution which forms 
a more or less distinct, and at times, double projection into the cavity 
itself. This projection (Hippocampus minor, eminentia unciformis, 
calliculus, unguis, calcar avis) was well described by Morand, and after 
him was called the ‘Spur of Morand ’—‘ Ergot de Morand.’ 
“The Hippocampus minor exhibits differences in its form and 
1 German edition, by Hein, under the title, Anatomie und Physiologie des Nerven- 
systems des Menschen und der Wirbelthiere, 1847, Bd. i., p. 463. 
