JENKINS AND Carson, Nervous Impulse in Worms. 285 
TABLE XIV B. 
Summary of experiments on Glycera rugosa. 
Postero-anterior rate. 
No. of No. of records Length of ‘ 
: : Rate in cm. 
experiment Distal | Proximal cord in cm. 
ear ve | i | 7 15 | 420 
2 2 2 18 | 514 
3 | 7 | 7 13 540 
ee NTs i aE 18 | 265 
Mean rate: 435 cm. per sec. 
Standard deviation: 106. 
Coefficient of variability: .24. 
TABLE XV. 
Summary of the rates in the fourteen species worked on. 
ki é _. | Coeff 
Species Direction Race ks cient of 
individuals | in cm. Res 
vari’ bility 
Cerebratulus sp. Postero-anterior 2 5-4-9.0 ah 
Aulastomum lacustre oe oe 13 56.0 .28 
Cirratulus sp. ag ne | 6 | go-0) |) :01g 
Arenicola sp. Antero-posterior 3 eu 2O208s oy 
Bispira polymorpha Postero-anterior IO 6940 | .13 
Aphrodite sp. Antero-posterior 2 54-5 .04 
Polynoe pulchra Postero-anterior 2 293-0 | .19 
Sthenelais fusca ne ye | I 205.0 
Eunice sp. ae < | 4 466.0 .09 
Nereis sp. se ck 5 165.0 .19 
Nereis virens at a I 89.0 | 
Ge oe Antero -posterior I 73-4 
Lubriconereis sp. (a) |Postero anterior 2 45-241 
ef * (Bb) a oe 7 49-937 
ae «« (b) |Antero-posterior 3 42-160 
Glycera rugosa Ob SS 9 433-0 .20 
. ck Postero-anterior 4 435-0 24 
page 268), Bispira (table V, page 272), Eunice (table IX, page 
277), Nereis sp. (table X, page 278), and Glycera (table XIV, 
page 284), the number of individals worked and the relative 
constancy of the individual rates seem to allow the conclusion 
that the mean of the individual rates is representative for their 
respective species. The mean in the groups represented by 
by two or three individuals only is of less value, especially in 
the two species of Lumbriconereis (tables XII and XIII) where 
the individual variations are so great. But in some species 
