VoutumeE XIII. 1903. NUMBER 4. 
oR ELE 
JournaLt or Comparative Neuro.oey. 
Pie RARE OF THE NERVOUS IMPULSE IN. THE 
VENTRAL NERVE-CORD OF CERTAIN WORMS. 
By O. P. JENKINS AND A. J. CARLSON. 
(From the Hopkins’ Seastde Laboratory and the Physiological Laboratory of 
Leland Stanford, Jr. University.) 
With 14 Figures. 
The physiological properties of the muscles in different 
species of worms have been investigated by BrEDERMAN (1, 
1889), Furst (2, 1889), UrxkitLy (3, 1896), Borrazzi (4, 
1898), SrrauB (5, 1900), and BuppincTon (6, 1902), and 
the physiological effects of sectioning the ventral nerve cord, 
extirpation of portions of the same, and extirpation of the 
cesophageal yanglia have been studied by Logs (7, 1894), 
FRIEDLANDER (8, 1894), and Maxwett (9, 1897); but no 
observations on the rate of propagation of the nervous impulse 
appear to have been made in this phylum. In this paper we 
record some measurements, done by the graphic method, of the 
rate of nervous impulse in the following species: 
Cerebratulus sp. Sthenelais fusca Johnson 
Aulastomum lacustre Eunice sp. 
Cirratulus sp.? Nereis virens Sars =N. branti Ehlers 
Arenicola sp. Nereis sp. 
Bispira polymorpha Johnson Lumbriconereis sp. (a) 
Aphrodite sp. Lumbriconereis sp. (b) 
Polynoe pulchra Johnson Glycera rugosa Johnson 
1 The two nemertians worked on were identified for us by Professor R. W. 
Cok of Yale University as belonging to this genus, species probably new. 
2 The marine annelids were identified for us by Professor H. P. JOHNSON 
of Harvard University. Some of them are new species described by Professor 
