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A PLAINLY WORDED BIOLOGICAL QUARTERLY. 



VOL. I. No. 2. FEBRUARY, 1894. 



THE BEARING OF STARFISHES IN CONFINEMENT. 



BY H. J. WADDINGTON. 



PROBABLY of all the Echinodermata, Asterina is the most easily- 

 kept in small aquaria. The conditions for successful develop- 

 ment are very simple, and the results more than repay the trouble 

 expended. 



In 1889, I commenced keeping a few Asterina gibbosa in a 

 small bell-glass holding about 1 gallon of water. These were fed 

 on small pieces of oyster every week, and remained in perfect health. 



In May the ova were discharged, they rapidly rose to the surface 

 of the water, coalesced and quickly decomposed. 



The failure, in this instance, was no doubt owing to the seawater 

 being above the normal density. In 1890, the ova from the same 

 Asterince were again discharged, and although I succeeded in entan- 

 gling a few among the filaments of some conferva, the remainder 

 rose to the surface and decomposed as on the former occasion. It 

 was evident that the conditions were unsatisfactory and must be 

 modified. I placed the aquarium containing the Asterince, and 

 which was covered with a piece of glass, close to a window with a 

 S.W. aspect, and allowed it to have all the light possible. In a short 

 time the aquarium was covered with vegetation which increased 

 rapidly until May, 1891. 



The ova were now deposited on the side of the aquarium, each 

 ovum quite separate. In no case were two ova touching one another. 

 The subsequent development was all that could be desired. I was 

 equally successful in 1892 and 1893. 



The ova are deposited towards the end of May (26th or 27th) ; 

 in each of the years 1891-2-3 there has not been a variation of 

 more than two days in the date of deposition. The ova are not 

 all deposited at one time, as in 1892 from two Asterince were 

 deposited 3 patches of eggs at intervals of .a. few. hours. .... 



