Mr Potts, The Swarming of Odontosyllis. 195 
was with great interest that I discovered and read a paper by 
Galloway and Welch* on very similar phenomena in an Atlantic 
species Odontosyllis enopla. In the summer of 1904 this species 
was observed to appear in the surface waters of Harrington Sound, 
Bermudas, in considerable numbers and with striking regularity. 
The following dates of appearance are chronicled : 
July 3—7 reaching a maximum on the 4th, 
July 29—31 _,, rn 2 S 30th, 
August 23 (no further details), 
Five Fingers 
YM © 
Departure 
Bay. 
Newcastle 
Tsland. 
Cabriola 
Tsland 
3 Mcles. 
Nanatmo. 
Qrea of sea bottom se whuck 3 
/phosphorea was Avedged . 
Localuby where Swarmng forms 
weve observed 
Dien oF © ehosphorea.. 
so that there appears to be an interval of approximately 26 days. 
On the two first occasions when they were carefully observed they 
appeared each day within fifteen minutes of the same time just at 
twilight. The daily period of swarming lasted from 20—30 minutes. 
“Only a few appeared at first each evening. The numbers gradually 
WLLL) 
* Trans. Amer. Micr. Soc., vol. xxx. 1911, pp. 13-39. 
13—2 
