386 TetrarJiynchus erinaceus 
fixation the usual purple of the sections faded entirely and left only a 
pure blue. It was evident that only the modified parenchyma in the 
nervous system had stained, with of course the muscle fibres in 
surrounding parts. 
Uors.Ani Bofhridia/ nerves 
Fig. 5. Schematic representation of one-half of the central nervous system seen as 
projected in a horizontal plane. The relative proportions of the various parts are 
fairly accurate, the figure having been reconstructed from serial sections. The darkly 
shaded parts are the approximate loci of the ganglionic cells. The main trunks of 
the excretory canal system are also shown. Mag. 90 dia. 
