MULTIPLICATION BY FISSION IN 

 HOLOTHURIANS^ 



DR. W. J. CROZIER 



There is to be found in various text-books the state- 

 ment that certain pedate holothurians are capable of 

 spontaneous transverse division, each part so formed 

 producing a new individual (Lang, 1894, p. 1095; Morgan, 

 1901, p. 144). This opinion seems to be based, so far as 

 I can learn, upon the observations of Daly ell (1851, p. 

 74; PI. XIV), although Morgan says that ''more recent 

 observers have confirmed this discovery." Chadwick 

 (1891), also, found small individuals of Cucumaria planci 

 to undergo self-division, and in one instance the posterior 

 portion so formed also divided. These are records of 

 division in holothurians which were being kept in small 

 aquaria, and there 1ms been no evidence, so far as I am 

 aware, going to show that self-division of adult pedate 

 liolotlnirians is a method of propagation among these 

 aiiinials in their normal surroundings. Hence the possi- 

 l;ility of non-sexual reproduction in this way is usually 

 ^tat.Ml with reserve (cf. Lang, 1894). 



In otlu'i- classes of echinoderms (aside from ecliinoids) 

 tlie oxi)edient of reproduction by fission is of course not 

 unusual; ])ut in ophiuroids and in such starfishes as 

 L'nickia (Clark, 1913) andiCoscinastenas (Crozier, 1914), ^ 

 we are dealing with the division or fragmentation of a 



1 (ontribntions from the BornuMla Hlolo-r,-al Station for Bcsoarch, No. 66. 



2 1 havo boon al)lc to seoure furtlu-r cvi^lrncn retrar^liri^r the fragmentation 



aro in.loe.l valiil. This pvi.lonro will ho [.ublishrMl in connection with a de- 



ThJ presence of frreat variation in ray-length, as well as of a variable num- 

 ber of ma..]reporites, gives an opportunity to test out in this species the 



560 



