EGG- LAVING HABITS OF AMPHITRITE OKNATA VERRILL. 329 



Probably two thirds of the tubes are within six inches, in a ver- 

 tical direction, of this low water line at spring tide. The worms 

 are more abundant on flats which are somewhat protected from 

 strong currents. When the tide is running and the water com- 

 paratively shallow, it is quite common to see the worms at one 

 of the openings, apparently feeding, the mouth just below the 

 pit of the "volcano," and the numerous tentacles extending out 

 for several inches in radial directions. It was found impossible 

 to observe the deposit of sexual products under natural condi- 

 tions, and this careful description of their habitat is given in 

 order that we may better interpret the results obtained in the 

 laboratory. 





 I. TIME OF EGG-LAYING. 



Verrill in 18/12 described the occurrence of an annelid in 

 Vineyard Sound to which he gave the name Amphitrite ornata 

 Verrill. Several years later he gave the credit for the original 

 description to Joseph Leidy who in 1855 had described what ap- 

 pears to be the same species under the name of Terebella ornata 

 Leidy. No mention is made of egg-laying habits in either of 

 these papers. To Mead belongs the credit of recording the first 

 observations of this kind. He writes : " The limits of the breeding 

 season are unknown. Although about eight hundred worms 

 were collected in lots of twenty or thirty between the first of 

 June and the last of August, only seldom were ripe eggs and ripe 

 spermatozoa obtained. It is useless to cut the worms open, for 

 if the sexual products are mature, they will be discharged, usually 

 at about six o'clock in the evening, more often on the day of 

 capture, sometimes the next day." I found little difficulty in 

 verifying most of these results. 



Amphitrite must necessarily be collected in the day time and 

 when the tides are low. They were collected in quantities, from 

 twelve to seventy-five specimens in each lot, and it is estimated 

 that about two thousand adult worms were examined in the 

 course of the four seasons during which their habits were under 

 consideration. When dug they were washed free from the mud 

 tube and placed in a bucket of sea-water to be carried to the lab- 

 oratory. At times the males and females were placed in separate 



