250 AMPHITRITE. 
quite visible, both during transmission into the tentacula and as they 
return. But I have not been able to ascertain whether the ascent there 
and the return are by different channels. 
PiaTe XXXI. 
Fias. 12. 13. Amphitrite luna. 
3. FILIPORA FILOGRANA.—Plate XXXIV. Figs. 1, 2, 3, 4, 5, 6. 
Some authors propose to incorporate this product with the Zoophytes ; 
but its proper position seems between the Amphitrite and the Serpula, 
for it consists of a tube, originating from one of the Annelides by which 
it is occupied. 
The Filipora filograna is a marine product, generally recovered 
from deep waters. It constitutes irregular masses, composed of a vast 
congeries of shelly tubes, alike irregular in dimensions and arrangement, 
formed from a minute animal, closely allied to the Amphitrite. 
There is no uniformity either of size, shape, or appearance, among 
the different masses : no two are alike. Their formation can be scarcely 
said to be regulated by any common laws, which may be partly ascribed 
to every tube originating from a different animal, whose numbers do not 
seem under any known modification. 
This animal extends in whole about three lines. It consists of a 
vermicular body, crowned by a plume of eight pinnate organs, each com- 
posed of a rib as before, bordered by about fourteen cilia, rather thick 
and obtuse. The body is composed of about twenty-four segments, each 
with a pencil of several bristles on both sides. It originates, as in the 
Amphitrite, in a kind of frill, and terminates with two small tubercles. 
The plume forms a funnel, equalling a third of the length of the 
body. No antennular organs within it could be detected by the micro- 
scope. But, interception of the neighbouring parts precluded a distinct 
view of the centre. 
