SHORTER ARTICLES AND CORRESPONDENCE 



OBSERVATIONS ON THE SPAWNING HABITS OF 

 HYDROIDES DIANTHUS 



In connection with experiments and observations on the be- 

 havior of several species of annelids, chiefly the one above 

 named, covering a period of several years, it was my good for- 

 tune to have seen the apparently somewhat rare phenomenon of 

 the spawning of these annelids under circumstances peculiarly 

 favorable for observation. So far as I am aware this has not 

 been made a matter of record, at least for this species, and some 

 inquiry among students of the group has failed to elicit any 

 detailed knowledge concerning the subject. It seems to be worth 

 while to submit my notes made at the time for at least a record 

 of fact, trusting that they may prove interesting to that extent. 



The observations were made upon specimens in an aquarium in 

 my room at the Fisheries laboratory, Woods Hole, on July 30, 1908. 

 A large colony, or aggregate, of these annelids had been freshly 

 obtained from near New Bedford, and had been transferred to 

 my aquarium about two hours before the spawning took place. 

 This was soon after noon of the date mentioned and the first ap- 

 pearance of the discharge took place about two o'clock. I was 

 sitting quietly by the aquarium observing the various aspects and 

 attitudes of the specimens, when a single individual was seen 

 to discharge suddenly a jet of whitish matter, which seemed 

 like a milky spume. It was so unusual as to attract imme- 

 diate attention, and within a few seconds the same specimen 

 repeated the process. Almost immediately a second specimen 

 made a similar discharge, ejecting a cloudy mass in a jet which 

 extended from twenty to thirty millimeters from the worm, 

 which at the time was extended perhaps about half that dis- 

 tance beyond the orifice of the tube. Almost immediately 

 another specimen exploded in similar fashion, and in less time 



products. The eggs soon settled downward, indeed at the time 

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