126 Experiments on the Development of Peripheral Nerves 
abdominal walls, which were used especially for study, because it is only 
there that one can distinguish clearly between motor and sensory rami 
(Fig. 3). The results of ten ° experiments were as follows: In seven cases 
sensory nerves were found in the abdominal walls, but no motor (Fig. 5), 
although the sheath cells, as shown particularly in one case, were in very 
Fic. 5. Semidiagrammatic view of the nerves of the abdominal walls of a 
frog larva from which the ventral half of the spinal cord had been removed at 
the stage represented in Fig. 1. Absence of the purely motor rami, which 
normally run in the inscriptiones tendinee. 
close proximity to the point where the terminal motor rami normally 
arise ; often, however, the sensory nerves were not so well developed as in 
° Bach side of each individual specimen is counted as a case, because, as 
far as the factors in the experiment are concerned, the two sides of the body 
are mutually independent. 
