286 
Transactions of the Society. 
The object of intercommunication is now well known to be an 
interchange passing through the protoplasmic network attached to 
all the organs, and from which all can obtain nourishment lor their 
growth. This parenchym occurs in greatest abundance round the 
caecum, from which it no doubt absorbs the digested food, but when 
the polypides die down — if we must so call it — the colony would 
soon become a dead skeleton were there no interchange of living 
material. The direct communication with the surrounding sea-water 
is often somewhat similar, for the shell of many species is ornamented 
with pores, or, as I have called them, pore-tubes, formed by a chitinous 
or integumentary tube containing coloured corpuscles, but these tubes 
are usually closed at both ends by a membrane or disc, and in some 
cases the structure of these discs must be compared with the rosette 
plates. The frequent death of the polypide has necessitated various 
contrivances by which the colony may be kept in health when there 
are few or no active polypides. 
In no species of Flustra have I found the suboral glands* * * § to 
which I have called attention in various papers. 
Before turning to the detail consideration of a few species, I 
would point out that a better acquaintance with Flustra proves that 
their geographical distribution is much more limited than in most 
genera. 
We now see that the northern seas and the Mediterranean only 
have F. securifrons in common, and, as far as I am aware, of the 
South African fauna only F. dentigera (an Australian form) is found 
elsewhere. Of the South American species, F. biseriata and F. elegans 
occur in the Australian seas, and F. ovoidea in the South Indian 
Ocean ; then of the thirteen known species from the Australasian 
seas, only the three mentioned occur elsewhere. Of the three J apanese 
species Ortmann considers one is F. carbasea, a form occurring in the 
northern seas of Europe. 
The following table shows the distribution of species that can be 
recognised from the descriptions : — 
Northern F. f carbasea, securifrons, membranaceo-truncata , Barleei , 
papyracea , serrulata, pedunculata, foliacea,% oblonga. 
Mediterranean . . . securifrons, papyrea , tenella, pusilla. 
South African . . . . dentigera, armata, spinuligera, bomb))cina.§ 
Australian . .. .. dentigera, biseriata, elegans, denticulata , cribriformis , 
dissimilis , indivisa, pisciformis, mosleyi, reticulum , episco- 
palis, militaris , obtecta. 
South American . . biseriata, ovoidea, elegans. 
South Indian Ocean . . ovoidea, crassa. 
Japan carbasea, rhizopora , spoliata. 
* ‘ Gland-like Bodies in the Bryozoa,’ Journ. Linn. Soc. Zool., xxiv. p. 272, pi. xix. 
t Species printed in small capitals occur from a second region, 
j Flustra foliacea does not occur in the Mediterranean. Hincks, on the authority 
of Kirch enpauer, gives it from China and Algoa Bay, but this should be re-examined. 
§ I have this from Cape Agulhas, Port Elizabeth, and “ S. Africa,” and recent 
authors have only mentioned it from S. Africa, nor does it seem probable that this is 
