HUXLEY OX THE RELATIONS OF MAX TO THE LOWER ANIMALS. 77 



be regretted that so inadequate a figure should have been taken as a 

 typical representation of the Chimpanzee's brain. 



3. The Hippocampus minor. — But even supposing that the posterior 

 cornu of the lateral ventricle and its appendage, the hippocampus minor, 

 were absent in the apes, and " peculiar to the genus Homo," what 

 classificatory value would the distinction possess ? This, of course, de- 

 pends upon the constancy of the supposed distinctive character ; but it 

 so happens that, as every anatomist knows, the posterior cornu and the 

 hippocampus minor, are precisely those structures which are most va- 

 riable in the human brain. This is by no means a novel discovery. The 

 work of the brothers Wenzel* has now been published nearly half a 

 century, and it contains (pp. 144-146) the following account of the 

 special researches of these observers on the posterior cornu and the hip- 

 pocampus, which they call simply " Tuber" : — 



" Tuber in cornu posterior ■<? ventriculorum lateralium : — Non semper plerumque tamen 

 aclest, et quidera utroque in latere sive in utroque cornu. Inter quinquaginta et unum, 

 eo specialiter fine a nobis examinata cerebra diversa? omnino aetatis atque utriusque sexus, 

 tria tantum reperiebamus in quibus tuber iilud in utroque latere et duo in quibus uno in 

 latere desiderabatur. Quam constans autem, in universum tuberis istius prsesentia, tam 

 varans est magnitudo illius, non in diversis tantum subjectis, sed etiam in uno eodemque 

 absque omni prorsus et aatatis et sexus discrimine. Qnandoque admodum longum, inter- 

 dum latum nonnunquam valde angustum est. Magnitudo illius in universum spectata, 

 sequitur magnitudinem posterioris cornu ventriculorum lateralium : hsec quam maxime 

 diversa est, quin et in uno eodemque cerebro et utroque latere. Qnandoque enim cornu 

 istud fere usque ad posteriorem cerebri marginem pertingit, ssepe terminus prope initium 

 est, Sfepe contingit ut in minore cornu magis, in majore minus sit tuber, id quoque eodem 

 nonnunquam in cerebro evidentissime animadvertitur. Rarius in boc tubere est quod 

 sictit hippocampus ad finem suum crenas sive sulcos habeat quod superficies ejus duo in 

 tubera superius atque inferius, divisa sit ; plerumque autem in medio latissimum est et 

 crassissimum. in terminis angustius: sed et hoc quoque varium est. 



" Situs illius atque interior structura semper sunt eadem. Semper juxta interius latus 

 cornu videtur, ideoque superficiei cerebri prope adjaeet, idque cum interiore ejusdem 

 structura cohoeret, quae, ut sectio in transversum ducta clare demonstrat, eadem omnino 

 est ac in gyris cerebri. Constat videlicet ex interiore in laterales ventriculos continuato, 

 sive prolongato pariete cujus gyri in superficie cerebri siti, qui inflectitur, ac deinde in- 

 terior! de parte exteriorem versus ad superficiem cerebri rediens in alium gyrum transit. 

 Paries ist intra cornu medullosa, quoe cornu ipsurn vestit, lamina obducitur; paries ipse 

 autem ex cinerea, in ambitu cerebri sita, ubique conspieua substantia constat, quas hoc 

 loco neque latior est, neque alium colorem exhibet ac in quovis alio cerebri gyro. 



"Inter utrumque tuberis parietem spatium invenitur, quod vasculosa cerebri reque 

 explet ac sulcum inter duos alios gyras in superficie cerebri sitas. 



" Si in superficie cerebri eo, qui eminentise 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 exteriors cerebri superricie sitis omino simile, quoad in- 

 teriorem vero structuram plane aequale, in interiore cerebro sive in aliqua ventriculorum 

 ejusdam parte existens gyrus sit ; quod e contrario hippocampus, si cum gyris in super- 

 ficie cerebri existentibus comparatur, tantummodo gyri alicujus pars, non autem abso- 

 lutus atque integer gyrus sit, cujus initium in interiore cerebro, aut in aliqua ventricu- 

 lorum parte existit." 



* Jos. et Car. Wenzel, " De penitiori structura Cerebri Hominis et Brutorum. 

 Tubings, mdcccxii. 



