280 JoURNAL OF COMPARATIVE NEUROLOGY. 
TABLE Xi. 
Summary of experiments on Nereis virens. 
No. of | No. of records Length of : 
s : Rate in cm. 
experiment Distal | Proximal cord in cm. 
I | 
(antero-posterior) | 27 | Ig 6.5 73-4 
5 | 
(postero-anterior) | 13 | II | 20.0 | 89.0 
Lumbriconereis sp. (a). 
Small specimens of this species of 20 to 30 cm. and from 
2 to 3 mm. in diameter are very abundant in the gravel at the 
lower limits of the tide, but only one large specimen was se- 
cured. This was 75 cm. in length and from 6 to 7 mm. in di- 
ameter, but the specimen was accidentally broken in two pieces 
in being captured. The anterior portion proved of great ser- 
vice since since 150 good records distributed over a period of 
three days were obtained from it. The posterior portion failed 
WIVWVYIIJIIIIIVIYJYAPJIPIPIWIIVIIVIJIJIJI(II{IIIIIIIJPIPAIIPADIIIIIN 
Fig. 12. Lumbriconerets sp. (a) Postero-anterior. Length of nerve cord be- 
tween distal and proximal electrodes: 21cm. Rate: 262.5 cm. per sec. 
Time: 50 d.v. per sec. 
to give equally good results from the fact that in attempting to 
prepare it for experimentation it went into a strongly contracted 
state which continued for three days, although left undisturbed 
in the aquarium. During this time it failed to react to any 
stimuli. This same phenomenon has been observed in some of 
the specimens of Glycera which had been injured. The smaller 
specimens of Lumbriconereis gave so much trouble in this way 
that but few records were obtained from them. These are the 
only free swimming polychetes in which this phenomenon was 
observed. 
