240 THEODORE H. BULLOCK 



in the pleurovisceral connective, confined to the right side (Tauc) whereas a 

 spike similar to the smaller one is also found in the left pleurovisceral con- 

 nective (Goldman). Whether the giants end in one of the periesophageal 

 ganglia or send branches into peripheral nerves and therefore whether they 

 are interneurons or motoneurons is not known. The largest giant does not 

 appear to send branches into visceral nerves. 



Only one further anatomical point will be made here. The axons of several 

 giant cells can be found to come into intimate contact in the neuropile, 

 forming an interweaving tangle such as that shown in Fig. 7. Doubtless there 

 are small collaterals making synaptic connections in the fine textured neuro- 

 pile as is usual for large invertebrate unipolars, but we have not visualized 

 these as yet. 



These fragmentary notes may serve to emphasize the need for a thorough 

 anatomical account of this important physiological preparation. Much could 

 be done by electrical tracing of both afferent and efferent connections. 



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