274 JOURNAL OF COMPARATIVE NEUROLOGY. 
drate nor decapitation serving to quiet it. These obstacles 
prevented our obtaining satisfactory records from more than two 
specimens, although many specimens were attempted. The 
preparation fatigues quickly and single induction shocks, unless 
very strong, were not always efficient. Only the postero-an- 
terior rate was determined. Another species of this genus, 
Polynoe brevis, is common at Pacific Grove, but as it reaches 
a length of only 2 or 3 cm. no records could be taken from it. 
wal. BAN sc eae aa re 
a I oe 2 ee ee 
pal SPAS EEN NE PALL) a SRE Oot 2 UE eh ee 
GVA LPALDMPSPSPPISSISSS SSIS ISIN III. 
Fig. 7. Polynoe pulchra. Postero-anterior. Length of nerve cord between 
distal and proximal electrodes: 3.5cm. Rate: 350 cm. per sec. Time: 
50 d.v. per sec. 
EXPERIMENT No. 1, Table VII, postero-anterior, temp. 13°C, Aug. 16, IgoI. 
Distal Proximal 
No. of records 2 2 
Mean latent time 0.127 sec. 0.110 sec. 
Standard deviation 0.004 sec. none 
Coefficient of variability .03 none 
Length of cord: 4 cm. (33 segments). Rate: 230 cm. per sec. 
TABLE VII. 
Summary of experiments on Polynoe pulchra. 
Postero-anterior rate. 
No. of No. of records Length of ’ 
: : : Rate in cm, 
experiment Distal Proximal cord in cm. 
I 2 2 4 236 
2 2 2 3.5 350 
Average rate: 293 cm. per sec. 
Sthenelais fusca. 
This worm seems to be rare at Pacific Grove. Satisfactory 
records for a single specimen only were obtained, and these are 
of the rate of the impulse in the postero-anterior direction. 
