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there is a statement to the effect that there is some indication of 

 an abdominal ganglion back of the cephalo-thoracic mass in 

 psendoscorpions. I have made series of Chelifer as well as a 

 large number of dissections and have found no indication of 

 such a ganglion in any of the specimens. 



Methods. Due to the very resistant chitin it was very difficult 

 to make good serial sections. Fluids which softened the chitin 

 to any degree, ruined the internal organs at the same time. A 

 few perfect series were obtained through the bodies of some of 

 the younger specimens, but with the older ones it was necessary 

 to remove a large part of the chitin of the body-wall, or to 

 remove the nervous system entirely. 



Figure 1. The central nervous system of Chelifer. H, the nervous system from 

 above, showing sonie of the nerves, cells and groups of cells which 

 may in part represent ganglia and some of the tracheal tubes in the 

 nervous system. The brain is at the top of the figure. I, central 

 nervous system of Chelifer shown in ventral view. The palpal nerves 

 are those at the top of the figure. Compiled from several nervous 

 systems. X50. 



Most of the usual neuroglical methods were used, such as those 

 of Golgi, Cajal and methylene blue, but with small success. The 

 best preparations were obtained by fixing in Flemming's fluid 

 and staining on the slide with methylene blue, neutral red or 

 hematoxylin. For a clear idea of the form of the ganglion and 

 nerves, dissections were made of fresh and preserved specimens. 

 Usually the dorsal body-wall was removed in one piece and the 



