SMALLWOOD. 



POLYCERELLA ZOOBOTRYON. 



627 



region. Each cell is of the usual unipolar type, and while many send 

 their axons directly into or through the cerebral mass, others send 

 theirs for some distance between other cells before leaving the ganglion. 

 The center of the ganglion is occupied by a feltwork of nerve fibres. 

 Axons in small groups course through this feltwork and pass out into 



Figure 11. Parasagittal section of the right pedal ganglion, co'nt.cb.-pd., 

 cerebro-pedal connective; ivlr.tis.co'nt., connective-tissue sheath; n'gli., 

 neuroglia; n.pd.a., anterior pedal nerve. 



the pedal nerve. Axons in the pedal connective can readily be traced 

 through the ganglion into the pedal nerve. The neuroglia cells (Fig- 

 ure 11, n'gli.) are few in number and found only around the periphery 

 of the ganglia. 



The larger of the nerve cells give a more pronounced reaction to the 

 various reagents than the smaller ones do, although no constant struc- 

 tural differences are observable. The nucleus is proportionately very 

 large and rich in chromatin, while the cytoplasm is finely granular and 

 contains a few vacuoles. In fixation with Hermann's fluid there are a 

 number of blackish bodies in the cytoplasm, and bodies apparently sim- 

 ilar are found in the ganglion outside of the nerve cells. Bodies having 

 a similar appearance are also present in the epithelial cells of the repro- 

 ductive ducts. These bodies are probably fat or related substances 

 blackened by the osmic acid contained in the fixing fluid. 



