Fish, The Tndusium of the Callosuni. 6y 



having its two walls composed of cinerea. The so-called cho- 

 roid fissure (rima) does not enter into the category of true fissures 

 except, perhaps, transiently at a very early embryonic stage. 



The physiological significance is largely hypothetical and, 

 as stated by Blumenau, awaits further elucidation. The strise 

 or longitudinal fibers of the indusium, as stated before, are con- 

 nected cephalad with the olfactory lobe and caudad with the fas- 

 ciola and thus indirectly, perhaps, with the temporal lobe and 

 are possibly correlated with the centers for olfaction. It is worth 

 noting, however, that we should, on this ground, expect a high 

 state of development of the indusium or strise in the macros- 

 matic animals. The order to which the cat belongs (Carnivora) 

 is preeminently microsmitic, and yet the indusium and its con- 

 stituents are less developed than in any of the other forms 

 studied ; man and chimpanzee are noteworthy examples of the 

 microsmitics, yet their indusiums are well developed. 



In conclusion, the writer wishes to acknowledge his indebt- 

 edness to Professor Wilder, at whose suggestion the piper was 

 prepared, for certain rare and well-preserved material placed at 

 his disposal. 



LITERATURE. 



1 L. Blumenau. Zur Entwicklungsgeschichte und feineren Anatomic des 

 Hirnbalkens. Arch. f. Mikr. Anat XXXVII., I. 189I. 



2 F. Marchand. Ueber die Eiitwickelung des Balkens im Menschlichen 

 Cxehirn. Arch. f. Mikr. Anat. XXXVII., 298-334. 189I. 



3 Kolliker's Gewebelehre. 



*Arch. f. Psychiatrie. Bd. III. 



* L. Stieda. Studien Uber das centrale Nervensystem der Wirbelthiere. 

 Leipzig. 1870. 



^ Giacomini. Giornale della r. Accad. Med. di Torino. 1883. 



'B. G. Wilder. Article, Brain. Supplementary volume of the Reference 

 Hand book of the Medical Sciences. 1893. [In Press.] 



^ E. Zuckerkandl. Uber das Riechcentrum Stuttgart. 1887. 



"V. Mihalkovici. Eiitwicklmigsje^chichte des Gehirns. Leipzig. 1877. 



'*' E. C. Spitzka. Article, Brain Histology. The Reference Handbook of the 

 Medical Sciences. Vol. VIII. 1889. 



