200 
ments carried out by Monticelli are of the greatest interest, 
showing this Holothurian to be one of the most wonderful objects 
for experimental studies on regeneration. Evidently the paper has 
been quite overlooked; I have not found any reference to it in 
literature, nor in Morgan’s well known book on regeneration, 
I am, therefore, glad to take the opportunity here to call attention 
to this most interesting paper, undoubtedly the most important one, 
hitherto published on this subject. 
In 1917 Crozier published an interesting paper on multiplic- 
ation by fission in Holothurians in which he gives the proof that 
this way of reproduction occurs normally in Holothuria surinamen- 
sis (Semper). He also observed H. captiva Ludwig to di vide spon- 
taneously in aquaria in the same way as observed for Cucumaria 
plcaici Brandt, but only one single adult of that species was found 
under natural conditions, in which there was evidence of regener¬ 
ation. He there States that „if H. captiva undergoes division norm¬ 
ally, it can only occur in very young stages“. (1917, p. 562). 
Multiplication by autotomy is thus known to occur, under normal 
conditions, only in the two species Cucumaria planci (Brandt) and 
Holothuria surinamensis (Semper). 
On the other hånd, there are evidences to show that other spec¬ 
ies of Holothurians possess a power of regeneration great enough 
to enable them to multiply in this way under casual circumstances. 
Thus M o n t i c e 11 i has seen a Cucumaria syracusana Sars, which had 
been cut into two pieces, regenerate into two complete specimens. 
According to Monticelli, Semper (I have not succeded in find- 
ing this passage in Semper’s work) has observed a case of auto¬ 
tomy and regeneration of both parts in Cucumaria versicolor Sem¬ 
per. _ Tore 11 e (1909) has observed that also Cucumaria Grubei 
Marenz., when cut into two equal parts, can regenerate in both 
parts, though, as a rule, the posterior part was found to possess the 
regenerating power to a much higher degree than the anterior part. 
To this must be added Crozier’s observations on H. captiva Lud¬ 
wig; further must be mentioned here, although not a direct case 
of autotomy and regeneration of both parts, that Benham (1912) 
has observed some specimens of Åctinopyga parvula (Sel.) from 
the Kermadec Islands, in which „there is an abrupt transverse 
line separating the dark anterior region from a posterior paler 
