638 



ZOOLOGICAL SOCIETY BULLETIN. 



CHANNELLED WHELK SPAWNING. SECOND DAY 

 Rear view of the sheU. 

 Photo by L. B. Spencer. 



pletion. Althougli tlic animal lias been under 

 almost constant observation in the New York 

 Aquarium for a dozen years, the spawning 

 process has never taken place there until re- 

 cently. 



On the morning of October i, 1909, a whelk 

 witli six of the connected egg-cases jjrotruding, 

 was found in one of tlie tanks. In the evening 

 when ten cases were visible, the animal was re- 

 moved for closer observa- 

 tion to a small tank of flow- 

 ing sea-water in the labor- 

 atory. By the next even- 

 ing there were sixteen cases 

 in siglit, and on the even- 

 ing of the (Jtii, twenty-four 

 cases. 



The spawning ])roceeded 

 steadily and the protrud- 

 ing egg-cases were counted 

 each evening. On the 7th, 

 twenty-nine cases liad ap- 

 peared, on the 8th, tliirty- 

 five. on the 9th, forty-two. 

 on the 10th forty-eight and 

 on tlie nth, sixty-three, 

 when tlie string of cases 

 seventeen inches in length 

 was complete. Tlie lengtli 

 of shell of tlie m o t h e r 

 whelk was eight inches. 



During the whole eiglit 

 days jirocess of egg-lay- 

 ing, the wlielk rested on the 



bottom of the tank with the 

 open side of the s ii e 1 1 

 turned upward and the 

 soft parts but slightly pro- 

 truding. The position was 

 not changed at any time, 

 but when the egg laying 

 was completed, the animal 

 at once turned and attached 

 itself to the glass front. 

 In nature the whelk buries 

 itself in the sandy bottom 

 at spawning time, the 

 string of egg-cases push- 

 ing up through tlie sand as 

 they are cast off. 



Professor Jungerstn 

 of the University of Co- 

 |)enhagen wlio called at 

 the Aquarium a few days 

 later, inquired as to the 

 exact portion of the body 

 from which the egg-cases 

 had been cast off, stating 

 that in his opinion, "Cunningham's explanation 

 on tliis I mint was incorrect." It is to be re- 

 gretted tliat the animal was not dissected before 

 the conclusion of the spawning in order that this 

 point might have been determined. 



Each egg-case of the whelk contains several 

 embryos, which after a period of development, 

 escape from tlieir membranous ease to lead in- 

 dependent lives. 



CHANNELLED WHELK SPAWNING. EIGHTH DAY. 



The egg-cases are shown floating diagonally across the picturi 



Photo by L. B. Spencer. 



