Gatty Marine Laboratory, St. Andrews. 161 
invariable. In the Neapolitan Salmacina edificatrix many 
specimens would seem to show shorter and more slender 
pinne on the filaments, which throughout are terminated 
by the enlarged cushions. 
The higher Polychzets, as a rule, have the sexes separate, 
but Filograna is hermaphrodite, and, moreover, increases by 
active budding, the buds rapidly developing sexual elements 
which may be shed or the ova may be fertilised internally 
and find exit as larve. All these processes exist, it may be, 
in one and the same colony, and it is not easy to explain 
why such diversity should oceur, or why such characters, if 
acquired, should not be more stable. 
There is little evidence of a struggle for existence in such 
a form, since the sea supplies at once food and calcareous 
matter everywhere ; yet the warmer waters appear to favour 
the development of larger processes at the end of the branchial 
filaments in certain cases, but this falls under environment 
rather than individual competition, for it cannot be supposed 
that the great size of these processes is necessary for the 
well-being of the species generally. Whilst they may be 
associated with the environment, yet under the same 
conditions small terminal processes may be present, just 
as in colder waters opercula may be present or absent 
in the same colony. In connection with the statement 
that the warmer waters seem to favour rapid spread of the 
species it need only be pointed out that, im contrast with 
the colder eastern waters of Scotland, Filograna flourishes 
luxuriantly in the genial waters of the Laboratory at Port 
Hrin and speedily blocks with its calcareous tubes the supply- 
pipes, whilst on the boats of Dongonab in the Red Sea it is 
equally, if not more, luxuriant. 
Sexual selection would appear to have little or no effect 
in producing the varieties, though special varieties of oper- 
cula or branchiz on a given site may owe their frequence to 
the qualities transmitted by parents, or by the process of 
budding from a nurse-stock. 
The coloration of the branchiz is a feature of moment, 
especially in connection with the incidence of light. This 
coloration is marked in the Australian forms and in those 
from the Red Sea, the Mediterranean, aud the south 
generally, though it is by no means inconspicuous in those 
of colder climes. Is this coloration protective where it is 
highly developed, or is it only ornamental? The great 
beauty, as well as the endless variety, of the branchial circles 
or fans of the Serpulids must have struck every marine 
zoologist, and therein Filograna agrees with its family ; 
but the pigment may have special physiological purposes to 
Ann. & Mag. N. /list, Ser. 9, Vol. iti, ia. 
