209 
6—7). Most of the buttons in the Atlantic form are, as Théel 
has pointed out, obviously curved, while they are very regular in 
the Pacific species and not so siender of shape. The tables in the 
first mentioned form are perforated by many small holes, while in 
the Hawaiian form there are generally eight holes. — It is quite 
evident from this comparison of the Atlantic and the Pacific „ Acti- 
nopyga parvula“ that they cannot be identical, but are really two 
Figs. 6—7. Calcareous spicules of Actinopyga parvula (Sel.) (Fig. 6) 
and A. difficilis (Semper) (Fig. 7). 170 /i. 
A comparison of the type of Actinopyga parvula (Sel.) with the 
Holothuria captiva of Ludwig gives the result that there is not a single 
character by which they can be distinguished, and there is not 
the slightest doubt that H. captiva is only a synonym of A. parvula. 
Unfortunately the type specimen of H. captiva appears to have 
been lost. At least I am informed that it is no more in the col- 
lection of the Wiirzburg Institute from which it was described; but 
still the description given by Ludwig is sufficient to identify it 
with certainty as the common, small Westindian species, the multi- 
plication by fission of which was mentioned above. 
It is very noticeable that the type specimen of A. parvula is 
regenerating its anterior end which faet has escaped the attention 
of Selenka. — 
The Miilleria flavo-castanea Théel is in colour and size quite dif- 
ferent from both the Floridan and the Pacific type. The type spec¬ 
imen is 10 cm in length, the dorsal side is white, spotted with 
brown around the papillæ, the ventral side is brown. The tentacle 
Vidensk. Medd. fra Dansk naturh. Foren. Bd 73. 
14 
