Fig. 5 Crescent-shaped bipolar cell lying 

 within the layer of circular muscles and between 

 the ventral pair of setae, c.b.c, crescent-shaped 

 bipolar cell; emu., circular muscles; cut., cutic- 

 ula; epid., epidermis; p.n., peripheral nerve. 

 Ramon y Cajal method modified. X 540. 



Fig. 6 Deep lying sensory cell on the ventral surface of the earthworm. 

 a.p., accessory process; emu., circular muscles; cut., cuticula; epid., epidermis; 

 l.mu., longitudinal muscles; 7n.f., main fiber; 7i.r., nerve ring; p.n., peripheral 

 nerve; s.p.c, pyramidal sensory cell. Immersion methylene-blue method. X 540. 



Fig. 7 A group of three cells from an epidermal sense organ, a.p., accessory 

 process; b.e.n., basiepithelial net; emu., circular muscles; m.f., main fiber; s.c, 

 sense cells. Immersion methylene-blue method. X 540. 



105 



