200 THE CEREBRUM, 



there are several layers of medium-sized pyramids, arranged in 

 columns. The prominent apical processes of these pyramids 

 collect in bundles and proceed outward to the stratum zonale, 

 separating the columns of pyramids and producing the striations 

 above mentioned. As the apical dendrites approach the olfactory 

 islets they branch richly. The axones of the pyramids run straight 

 to the white core of the gyrus or into the alveus. The pyramids 

 continue without interruption through the hippocampus into 

 the nucleus of the dentate fascia. The alveus, which forms the 

 ventricular surface of the hippocampus, is made up largely of the 

 axones of these pyramids; from the alveus they proceed into the 

 crus of the fornix. (4) A few fusiform or stellate cells lie next 

 the alveus. They belong to .the type of Golgi, the axone being 

 wonderfully branched. In function they are associative. It is 

 in the region of these associative neurones that the axones of the 

 pyramids bend and adjust themselves so as to enter the alveus 

 nearly parallel with its surface, hence the name stratum oriens 

 applied to it by Edinger. 



The jascia dentata (Fig. 62) is a free lip of cortex folded inward 

 anterior to the hippocampal fissure. It presents a type of struc- 

 ture, which is continued, forward, through the band of Giacomin 

 into the reflected part of the uncus; and which extends backward 

 through the fasciola cinerea into the gyrus supracallosus (longit- 

 udinal striae of the corpus callosum). It is similar in structure 

 to the subiculum, the first and the third layers only present a 

 marked variation. The stratum zonale is not so prominent as 

 in the subiculum; and the stratum radiatum is entirely replaced 

 by the nucleus fasciae dentatae. The nucleus is composed of pyra- 

 mids, of polymorphous and fusiform cells and their branches. 

 Their dendrites radiate toward the stratum zonale, their axones 

 proceed into the crus of the fornix. The dentate fascia is absent 

 in anosmatic animals (A. Hill). 



Trigonum Olfactorium, Area Parolfactoria (Broca}, Gyrus 

 Subcallosus and Septum Pellucidum, and Substantia Perjorata 

 Anterior (Figs. 26 and 28). These are the parts into which run 

 most of the fibers of the medial and intermediate striae of the 

 olfactory tract. They are more conspicuous in the embryo than 



