279 
YI . — Interzooecial Communication in Flustridm, and Notes 
on Flustra. 
By Arthur Wm. Waters, F.B.M.S., F.L.S. 
(Read 15 th April, 1896.) 
Plates VI F. and VIII. 
It has long been known that throughout the Chilostomata there is 
connection between neighbouring zooecia through rosette plates,* and 
in some cases the avicularian, radical, and ovicellular chambers com- 
municate with the zooecia in the same way. They have, however, 
been but very slightly studied, and scarcely used for purposes of 
classification. I first gave particulars of some in my paper on the 
Bryozoa of the Bay of Naples, published in the Annals of Nat. Hist. 
EXPLANATION OF PLATES. 
Plate VII. 
Fig. 1 . — Flustra serrulata Busk. Lateral rosette plates x 25. 
2. „ „ Rosette plate X 250. 
,, 8. „ „ Distal wall x 25, 
,, 4. ,, militaris Waters. Lateral wall, showing raised ovicells x 2{). 
„ 5. ,, „ Plate x 250. 
„ 6. ., „ Distal wall x 85. Fig. 7. — Ditto x 25. 
•„ 8. armata Busk. Lateral wall x 25. 
.,9. „ Distal wall x 25. 
„ 10. nobilis Hincks. Lateral wall x 25. 
„ 11. „ „ Distal wall x 25. The section is not satisfactory, 
and no doubt there are other details uot made out. 
„ 12. „ pisciformis Busk. Lateral wall X 25. 
„ 13. „ „ Distal wall x 25. a — Ditto x 85. 
„ 14 . — Euthyris bombycina Busk ? Distal wall x 25. Fig. 15. — Ditto x 85. 
.,16. „ „ Lateral wall x 25, showing raised ovicell. 
„ 17 . — Flustra dissimilis Busk. Lateral wall x 25. 
., 18. „ ovoidea „ „ x 25. 
.. 19. „ „ „ Distal wall x 25. 
„ 20. „ cyathiformis MacG. „ x 25. 
„ 21. „ „ Lateral wall x 25. 
„ 22. „ crassa Busk. „ x 25. 
* I am unable to see any sufficient reason for changing the name rosette plate, 
although there is often such a wide divergence from the diaphragm as first described 
in Zoobotryon pellucidus , nor does that description seem quite correct. Hincks 
speaks of a communication plate ; Levinsen also of a “ Forbindelsplader ” with 
pores in it ; Smitt speaks of a communication pore, and Busk, in the ‘ Challenger 1 
Report, p. 57, mentions interzooecial pores or discs. The name communication plate 
or pore is not satisfactory, as both have often been used as if it were a simple struc- 
ture, whereas the communication really takes place through the small pores in the 
rosette plate, and in each rosette plate there may be one or numerous pores. If we 
are to change a name because it is unsuitable in some subsequently discovered cast s, 
then nomenclature would become more complicated than it is at present. We all 
recognise the reason for the name avicularia in Bugula , and would not think of dis- 
carding it because the small dorsal avicularia of Retepora do not suggest a bird’s 
beak. 
