No. 009] MULTIPLICATION IN HOLOTIIVRLANS 



many-armed creature relatively deficient in morpholog- 

 ical centralization; whereas in Ciicimaria and in Holo- 

 thurla the body is compactly built, the animal much more 

 of a unified individual. Consequently the self-division of 

 these holothurians is not without interest, especially sin€e 

 in these cases the plane of separation is anatomically per- 

 pendicular to that employed among the astroradiates, and 

 it is the purpose of this paper to present evidence which 

 proves that adult specimens of at least one species, Eolo- 

 fhuria surinamensis Ludw., do as a matter of fact divide 

 transversely into two parts under conditions which must 

 he regarded as normal. Since these diidsions are not in- 

 frequent in large numbers of specimens, if not in a single 

 life-history, we must conclude that fission represents a 

 regular means of mutli plication in this species. 



A few years ago I found (Crozier, 1915?>) that about 

 10 per cent, of the oxaniplos^ of H. surinamensis which 

 were studied showed a condition of either the oral or of 

 the cloacal end whicli-on the basis of observed regen- 

 erations following ex]UM-imental cutting-I interpreted 

 ag representing regeneration, possibly as a consequence 

 of spontaneous self-division. Similar conditions have 

 l^een noted by others for some other species of holo- 

 tliurians. e. r,'., by Benham (1912, p. 130) for Acfinopijga 

 {MiilliTln) iHUTuln (Selt'iika). but tlu-y have usually been 

 reftMTcd to i-cuM'iUM-ation after injiiry ])y such bottom feed- 

 ing fislics as small sliarks. Dr. II. L. Chirk informs me 

 that he has found a corresponding state of affairs in some 

 Australasian holothurians, at least in regard to the oc- 

 currence in nature of specimens showing posterior re- 

 generation. 



I subsequently obtained young individuals of H. c(ip- 



to divide spontaneously in the hiboratory (Crozier, 1914, 

 p. 18), precisely according to the procedure figured by 

 Dalyell (1851) and by Chadwick (1891). Only a single 

 adult IL captiva has been discovered, however, in which 

 there was evidence of normal regeneration; this indi- 



