202 
The mode of regeneration being exactly the same in both spec¬ 
ies there is no reason for treating each species separately in the 
following record. 
The external signs of regeneration are, as described by Cro- 
zier, a thinner skin, more slightly pigmented than that of the 
original animal (Fig. 1). The deposits of the skin which are of the 
same shape in the new and the old part, are lying less closely in 
the regenerating part. One specimen of A. difficilis which had 
2 
Fig. 1. Actinopyga difficilis (Semper) in regeneration ; to the left a specimen regener¬ 
ating the posterior end, to the right one regenerating the anterior end. 1 / 2 . 
Fig. 2. Actinopyga difficilis (Semper); a specimen which has just completed division ; 
opened and turned inside out so as to show the closed 
posterior end. 2 /s. 
evidently just finished division had part of the intestine hanging 
free, in the same way as described by previous authors. 
Specimens having just finished division have the end where 
division has taken place quite closed, thus being without mouth, 
respectively anal opening (the last case is figured in Fig. 2) — 
only a paler spot on the smooth surface marks the place where 
the opening will be formed. 
The development of the tentacles which could be studied espec- 
ially well in A. parvula proceeds in this way that at first 10 tent¬ 
acles appear contemporaneously, in the shape of unstalked, simply 
buttonformed knobs, arranged in ftve pairs. The following tentacles 
appear without definite order till the total number 20 is reached. 
This result is somewhat different from that of Crozier, who 
found only 9—15 tentacles on the regenerating oral end in H. 
