86 BULLETIN OF THE LABORATORIES 



That portion of the cortex within the gyrus fornicatus is the stratum 

 griseum circumvoluta of authors. The ectal tract of this convolution 

 is the so-called lamina nuclearis. Meynert, with his usual morpholo- 

 gical insight, recognized in the fascia dentata the free margin of the 

 mesal portion of the manth. These relations are especially well seen 

 in Plate XVII. of Honegger's work. As Sala says, the sole difference 

 between these gyri and other parts of the mantle consists in the fact 

 that the cells are crowded into a single narrow layer. With the state- 

 ments of Sala respecting the histological relations we are unable at 

 present to agree, ist. That author describes the cells of the fascia 

 dentata (gyrus uncinatus) as splenial. We think that, when the cell body 

 is preserved, it differs from those of the gyrus fornicatus chiefly in size, 

 but it lies in a different plane. We are furthermore unable to discover 

 how the distinction between the protoplasmic and nerve process is 

 made out in cases where they are so similar. 2d. Sala states that the 

 large cells of the gyrus fornicatus are functionally connected with the 

 fibres of the alveus, while the apical processes subdivide interminably 

 and terminate in the processes of neuroglia cells. The nervous pro- 

 cesses may spring from either end of the cells and either pass directly 

 entad to the alveus or ectad to the fibre layer immediately adjacent 

 and then return to the alveus. If the evidence of our sections is to be 

 trusted, the apical fibres pass directly into the ectal tract while the op- 

 posite extremity of the cell subdivides dichotomously, producing such 

 a neuropilem as Sala himself figures, with which the alveus fibres may 

 communicate. 



It seems scarcely to be doubted from the course of the radix lat- 

 eralis that its fibres reach the surface of tht hippocampus and connect 

 either directly or indirectly with the ectal layer of this region. The 

 great mass of the alveus fibres are derived from the ental aspect of the 

 fascia dentata. Thus, according to our view, the lamina nuclearis and 

 superficial bundle of the fascia dentata are parts of the tract from the 

 radix lateralis. Strong confirmation of this suggestion is found in the 

 much simpler relations in fishes. (See forthcoming paper in Journal 

 of Comparative Neurology for December.) 



The Cerebral Cortex. 



The cortex of the precrucial lobe may be regarded as typically 

 motor, but even here there are many cells of the ectal series which 

 divide at once into two or more strong processes and these in turn 

 again divide dicotomously until a dense felting of fibres develops over 



