88 
walls from the very top (2500 feet) down to the deep basin of ca. 
300 Meters, now occupying the place formerly occupied by the 
larger part of the island, which was blown up by the eruption in 
1883. I shall not enter on that most interesting chapter: the hi¬ 
story of the repopulation of the island by plants and animals after 
the total destruction of all life by the eruption, but content myself 
with referring to the two most recent important contributions to that 
subject, viz. Docters van Leeuwen’s “The Flora and Fauna 
of the islands of the Krakatau-group in 1919”^) and K. W. Dam¬ 
merman “The Fauna of Krakatau, Verlaten Island and Sebesi” ^). 
As regards the marine fauna I may refer to the most interesting 
observations by SIuiter (in 1888—89) on the reappearance of the 
reefforming corals at the coast of Krakatau^). Here I may mention 
only some observations on the littoral fauna of the island. 
The North side of the Island is, as stated above, a vertical rock 
Wall, with some huge blocks at its foot, over which a heavy surf 
constantly washes. Here we find the animal community^ peculiar 
to such localities in the tropics, above all characterized by the 
Echinoid Colobocentrotus atratus, which is, with its pavement of thick, 
flattened spines on the aboral side and with its innumerable sucking 
feet on the oral side, eminently adopted to living in the strengest 
surf— indeed it does not occur in places with no heavy and constant 
surf. It feeds on the fine algal vegetation occurring on the rocks. 
A rather extraordinary faet is the occurrence of a small, white Pla- 
narian, which is constantly found under the Colobocentrotus^ where 
it is safe against being washed away. (This Planarian I have also 
observed living under Colobocentrotus on the rocky shores of Hawaii). 
Very interesting is also the occurrence of a small fish (Salarias sp.) 
in the same locality. The whole of its underside, head and body, 
acts as a sucker, and thus it is safe from being washed away by 
the surf. I found it exelusively on the vertical surfaces of the 
rocks, sitting in great numbers, quite close together, with the tail 
curved up along the side of the body, which gave it quite a parti- 
1) Annales du Jardin Botanique de Buitenzorg. XXXI. 
2) Treubia. III. 1922. 
C. Ph. SI u i ter. Einiges uber die Entstehung der Korallen-Riffe in der 
Java See und Branntweinsbai, und iiber neue Korallenbildung bei Kra¬ 
katau. Natuurk. Tijdschr. voor Nederl. Indié. XLIX. 1890. 
