87 
ca. 30 Meters, an occurrence quite unusual for this sort of Crinoid, 
ought to disappear from literature.^) 
The above mentioned community of Retiflustra and Stirparia, 
together with several smaller Hydroids a. o., was mainly found at 
Station 81, in the Southern part of Strait Sunda (comp. PI. III). 
In other places (especially Station 95, in Lampong Bay) a small 
thin-shelled Laganum was exceedingly numerous, while a few miles 
away (Station 97), on apparently quite the same sort of bottom a 
curious .Mollusc {Calyptræa sp.),was the dominant form. Another 
striking example was afforded by the two Stations 82 and 83, at 
Prinsen Biland in the southernmost part of the Sunda Strait. At 
both stations solitary corals were plentiful, but they were of diffe- 
rent sorts in the two places, although the bottom and other physical 
conditions would seem to be quite identical. Upon the whole, I 
would take the opportunity of emphasizing that even where the 
bottom is very uniform, the various components of the fauna are 
by no means always evenly distributed, but rather occur more or 
less in herds or aggregations, in some spots in great numbers, in 
others very scarce.^) 
A visit to the fine coral reef (an almost pure Åcropora-ree?) 
surrounding the small Huisman Island, close to the larger Island 
of Sebesi, resulted in the interesting find (first due to Dr. H. 
Boschma) of a number of Plococidaris verticillata, otherwise not 
so commonly met with. It lives way down among the old branches 
of the Åcropora. More interesting was, however, a visit to the Island 
of Krakatau itself, the rest of which now stands with nearly vertical 
h A. H. Clark, in his paper “Four new species of the Crinoid Genus 
Rhizocrinus” (Proc. U. S. Nat. Museum. XXXVI. 1909, p. 674) quotes the 
statement of Korotneff and suggests that the species “recorded” by 
Korotneff is possibly the large Rh. Weberi. As seen from what is 
set forth above it is not adequate to State that the Rhizocrinus was re- 
corded by Korotneff, which would imply that he had found it there 
himself. 
2) A similar statement is made by Semon in his book “Im Australischen 
Busch” 1896, p. 505. “Es lasst sich mit einem Wort meiner Ansicht nach 
nicht bezweifeln, dass eine Anzahl von Grund bewohnenden niederen See- 
tieren, besonders Stachelhautern, geradezu gesellig lebt”. It does, 
however, not appear that he means to extend this statement also to such 
forms as live in deeper water on a quite uniform bottom. 
