70 Journal of Ent<iinology and Zoology 



The abdominal ganglia are eacli supplied by two ventral tracheae. The dorsal 

 tracheae send vessels throughout the length of the branches on the dorsum of the 

 ganglion. Each ganglion is well supplied by numerous small iracheoles. 



The two candal ganglia present seme ditTcrences in the distribution of tracheal 

 eleme.^ls. The dorsal surfaces of the twenty-third and twenty-fourth ganglia is sup- 

 plied by six tracheae. X'eiitrally there is cne principal branch suppling both by 

 numerous tracheoles. 



Histologically the brain and other ganglia resemble mich those of the more 

 generalized Insects. I have found little difference in my specimens and those figured 

 by Saint-Remy (1890) of 5. Morsilans. The cellular masses of all my preparations 

 seem much less than those figured by Saint-Remy. The fiberous area of the brain 

 contains some indication of lobular masses. There are at least two sizes of cells 

 noticeable. 



In the abdominal ganglia the fiberous mass occupies rather more than half the 

 bulk. The cellular area, composed of several sizes of cells, is closely crowded. 



The caudal ganglia contain less bulk of the fiberous mass and a large area 

 of cells. The cells here seem to be all of approximately the same size and type. 



In all preparations, the nuclei appear large, the nucleoli show prominently. 

 Tigroid substances was noticed in a few of the larger, better stained cells, especially 

 in the brain. Fibrils were seen to enter into certain cells, and touch the nuclei. 



CONCLUSIONS 



1. The central nervous system of S. Folymorp/ia is ccmpcscd of twenly-four 

 generalized ganglia. The brain is less comple.x than that of the insects. 



2. Of the three primitive elements of the brai.i two only are externally apparent. 



3. Tracheae supplying the central nervous system art definitely arranged. 



4. The functional cells of the central nervous system are of several sizes, the 

 fiberous mass makes up the greater bulk of the ganglion. The cellular area is external 

 and relatively less abundant. 



5. Nuclei are large, nucleoli arc well markeil. Fibrils appear to come into 

 contact with nuclei. 



BIBLK)t;R.\PHY 

 Casf, S.: General Reactions of a Centipede. 1920 



Journal of F.nlomology and Zoology. 

 Ilrymon.ls: 1S9S 



Zur Kntwicklungsgcschichte der Chilopoden. 



Silzungslicr K. press. .Akad. Wissenschaft. 



Die Enlwicklungsgeschiechte der Scolopender. 



Zoologia, Heft. 33. 

 \fiifiort, George: 



Structure, Relations and ncvelupmcnl of the Nervous a id Circulatory 



Systems - - - in Myriopoda and Macrourous .'Xrachnida. 



Philos. Transactions of the Royal Society. 

 Saint-Remy, G: 



Contributions i I'ctude du ccrveau chez les Arlhropoiles Trachcates. 



Archiv. Zool. Exper. Tome V. suppl. 1887-90. 



(Contribution from the Zoological Laboratory of Pomona College.) 



1901 



