20 
able ganglionie swelling, and these are again connected with each 
other by a posterior commissure which is stronger than the inter- 
mediate ones (fig. 40, 32, N). Nerve-cells are everywhere present in 
the circumference of the pedal nerves all along the whole of their 
course (fig. 43 and 44). 
The third pair of nerves separately originating from the cerebral 
ganglion directly gives rise to the longitudinal lateral nerves in 
which a continuous coating of nerve-cells may similarly be detected 
and which are more closely applied against the bodywall, kept in 
position and attached by connective tissue. A regular series of trans- 
verse commissures, similar to those between the two pedal nerves, 
connect the two lateral with the two pedal nerves (fig. 40). The 
distance between two such commissures was in my specimens about 
0.6 mm. The presence of the lateral commissures was positively 
demonstrated in an unbroken series of longitudinal sections trans- 
verse to these commissures !). Owing to the great tenuity of these 
nervous commissures and to the intricate way in which they are 
fixed between the muscular bodywall and the intestine and surround- 
ed by connective tissue I did not succeed in demonstrating them 
with certainty i.e. uninjured, by direct preparation ; the sections how- 
ever permit of a more repeated and more rigorous controlling. 
Numerous smaller nerve-branches diverge laterally from these com- 
missures; part’ of them providing the muscular tunic.. At the point 
of junetion between the commissures and the lateral nerves there 
is a very slight ganglionie swelling; close to their origin from the 
pedal nerves these commissures on the contrary generally appear 
thinner. 
Ganglionic swellings of the pedal nerves at the root of the pedal 
commissures are not decidedly absent but appear to be more strongly 
marked in the posterior body-region, being anteriorly often hardly 
l) It is with all reserve that I mention the probable existence of similar 
latero-pedal commissures in Neomenia. My conviction about their presence 
in this genus is as yet, however, only based upon two consecutive transverse 
sections of Prof. v. Graff, each of which shows one half of an apparently 
latero-pedal commissure. 
