August 11, 1905.] 



SCIENCE. 



181 



o/IL 



The microscopic structure of the ganglion, 

 shown in Fig. 3, resembles that of a spinal 

 ganglion. It is surrounded by a covering of 

 connective tissue from which supporting 

 strands pass into the interior of the ganglion. 

 The ganglion-cells are arranged in clusters and 

 layers between the nerve fibers and connective 

 tissue elements. The nerve-cells are for the 

 most part bipolar (gn. cl.), but a limited num- 

 ber of other ganglion cells (gn. cl.'), with 

 angular outlines and several processes leading 

 from them, may also be seen, which suggest 

 the presence of multipolar cells. 





Fig. 2. Brain of adult Squalus acanthias, from 

 above, natural size. 



•-olf. gi. 



the olfactory nerve. Thereafter it branches 

 and passes to portions of the nasal epithelium. 

 In Squalus acanthias, Fig. 2, the central 

 ends of the nerve are located within the 

 median furrow of the fore-brain, and its gan- 

 glion (gn.) is near the base of the olfactory 

 bulb. 



... . ■■■■ ^ ^■:.^■l•;oiSl^^^^^i■■-•^V,^~■■ 







gn. cl. 







gn. cl'. 



gn. cL 



Fig. 3. Section of the ganglion of the new 

 nerve of Squalus acanthias, X oc. 2, obj. 2/3 in. 



Fig. 4. Partly diagrammatic figure of a hori- 

 zontal section of the brain of Squalus acanthias 

 six inches long. Showing portion of the central 

 and peripheral endings of the new nerve. 



The central terminations and peripheral dis- 

 tribution of the new nerve are shown in Fig. 4. 

 This is partly diagrammatic, being based 

 on a section in the horizontal plane of the 

 brain of a Squalus acanthias about six inches 

 long. Centrally, the nerve fibers enter the 

 brain substance, and after much branching 

 are distributed mainly within an eminence 

 upon a median infolding of the pallium. This 

 eminence is supposed to correspond to that 

 designated ' eminentia septalis ' by von Kupffer 

 in the amphibian brain. 



The study of serial sections shows that the 

 fibers of the chief branches of the nerve are 

 distributed, peripherally, to the olfactory 

 membrane, in the antero-lateral portion of the 

 olfactory cup. There are also some smaller 



