143 
food put befare them in the normal way. This has an important 
bearing on the problems of geographical distribution, showing how 
some forms may be able to live in places where they cannot nor¬ 
mally propagate, the natural conditions being unfavourable to the 
sexual products. 
Since about the middle of September Amphiura filifonnis had 
passed its breeding season, while A. Chiajei was now just entering 
into it, it was to be expected that the larvæ of the latter must 
be found in the plankton towards the end of September and in 
October in similar abundance as those of A. filiformis during the 
height of its breeding season (towards this time, the middle of 
September, they were much less abundant). As I could not stay 
at Kristineberg beyond the middle of September, I asked Dr. 
Ostergren to do me the service to get some good plankton 
samples for me in the course of October and send them to me 
preserved in alcohol, which he very kindly did. The examination of 
these samples was, however, a disappointment to me. They contained 
all the same larval forms that I had found during August and Sep¬ 
tember, but none which could be referred to A. Chiajei. Only one 
specimen was found of a larva which I had not observed there 
hitherto, viz. a young specimen agreeing closely with the young 
larva of Ophiactis halli , as described in my paper, quoted above, on 
the development of some British Echinoderms. Ophiactis balli is 
not known from the coast of Bohuslån, but as it occurs in Skagerak 
it is not at all surprising that the larva could be brought that dis¬ 
tance by the currents. The larva of Amphiura Chiajei thus still 
remains unknown. It is possible that the fairly numerous spec- 
imens of Ophiopliiteus manens found in these samples really be- 
long to A. Chiajei , in which case the larvæ of these two species 
would be hardly distinguishable. But it is also possible that the 
larvæ of A. Chiajei were not at all present in these samples on 
accoiint of some unknown reason. Nothing can be stated definitely 
about these questions, until the larva of A. Chiajei has been made 
known through direct experiments. 
The description of Ophiopliiteus maneus in „Nordisches Plank¬ 
ton" is based only on the younger stages; the faet that none of 
them had the postero-dorsal arms developed was then naturally ex- 
plained by their young age. The examination of a very great 
