ON NAUTILUS AND SOME OTHER ORGANISMS. 161 
Rakaiya from the mainland I have taken one larva of Poly- 
gordius in an advanced stage of metamorphosis, when the long 
body has grown out behind the trochophore. On the same 
occasion the “ Auftrieb ” contained also larvee of Squilla. 
6. Phosphorescence.—The astonishing phosphorescence 
which is to be observed when fishing with the tow-net at night 
in Blanche Bay is in large measure due to Copepods. and 
Ostracods. 
7. Ascidians.—The Ascidiau fauna here is richer than I 
expected to find it, since, as Herdman has pointed out, the 
tropics are not the metropolis of the Ascidians. 
The Didemnide, which form one of the most difficult groups 
of compound Ascidians from a systematic point of view, 
are strongly represented by red, white, yellow, and green 
varieties. 
Botryllus also occurs, though notcommon. I only know at 
present of two species—one very thin and white, attached to 
the lower surface of corals; the other thicker and purple, 
found growing on a T'ridacna shell. 
In regard to the compound Ascidians, I have been struck by 
the apparent absence of any member of the Polyclinide. 
The simple Ascidians are represented by numerous species, 
one of which especially has peculiarities of such a nature that 
I will describe it at some length, reserving an account of the 
other Ascidians for a future occasion. 
8. Styeloides eviscerans, n. sp.—In 1885, Sluiter 
described, in the ‘ Natuurkundig Tijdschrift voor Ned-Indie,’ 
Bd. xlv, a simple Ascidian, under the name of Styeloides 
abranchiata, n. gen. et sp., in which the branchial sac and 
intestine were absent. Such was the condition of the animal 
in other respects that Sluiter was led to suppose that this must 
be the normal state of things, and founded the new genus 
accordingly. 
In his extremely useful ‘‘ Revised Classification of the 
Tunicata” (‘Journ. Linn. Soc. Zovol.,’ vol. xxiii), Herdman, 
commerting on this species of Sluiter’s, says, ‘This is such 
an exceptional and remarkable case that I cannot help sus- 
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