696 A. Ff. Goldfarb 
determined by tbe extent of these injuries. It is certain that the 
operated animals required more time to produce a head than the 
control animals. 
Bg I 
i 
syn 1) 7 daar 
a aN L 
Figs. 15 to 16 Cross-sections through ventral portion of the earthworm 12 days after operation. 
Fig. 15 shows absence of nerve cord and proximal part of lateral nerves. Fig. 16 (section through 7th 
segment, i. e., through anterior end of nerve cord) shows presence of a few ganglion cells scattered 
among large numbers of smaller cells. CM, circular muscles; LM, longitudinal muscles; LN, prox- 
imal end of lateral nerve; N, space formerly occupied by nerve cord; NC, nerve cord; S, sheath of 
cord; J, intestine. 
