Papers from Dr. Th. Mortensen s Pacific Expedition 
1914 - 16 . 
IX. 
On some cases of multiplication by fission and of 
coalescence in Holothurians; with notes on 
the synonymy of Actinopyga parvula 
(Sel.). 
By 
Elisabeth Deichmann. 
I. 
While reproduction by fission is known normally to occur 
rather frequently among Ophiuroids and Asteroids, this mode of 
reproduction was hitherto only in two cases stated under normal 
conditions among Holothurians. 
The observations of Da 1 ye 11 (1851) and ofChadwick (1891) 
were made only on specimens kept in aquaria. It was, however, 
to be expected that the same process of autotomy would occur in 
the species observed: Cucumarici planci (Brandt), 1 ) likewise under 
normal conditions, and the proof that this was really the case was 
given soon after the publication of Chadwick’s note on this mat¬ 
ter. In 1896 Mon ti c el li published a most interesting paper: „SuIF 
autotomia delle Cucumaria planci“ in which are recorded not only 
observations on the autotomy of this species in aquaria, but proof 
is also given that autotomy occurs in nature. The different experi- 
*) D a 1 y e 11 names his species Holothuria badothriæ, but finds it to be ident- 
ical with Forbes’ Holothuria ocnus , that is to say with his Ocnus 
lacteus , viz. Cucumaria lactea. Since, however, autotomy has not been 
recorded by any other author to occur in Cuc. lactea , and as Dalyell’s 
figures recall very much those given by C h a d w i c k and M o n t i c e 11 i> 
it may well be assumed that it was really Cuc. planci on which Da ly el 1 
made his observations. 
