106 
Plumularia falcata ; on which it is very frequently abond# nt ‘ 
It is a small calcareous species and generally of a purple or 
purplish white colour. It grows on a narrow base, is creep* 
ing, and dichotomonsly branched in a revolute manner, Tl>® 
cells or tubes arise from the upper surface only, the lo«' er 
being plain or only striated from the positiou of the cel |s 
above; they rise in two rows from near the centre of e» c, j 
branch and diverge towards the sides, leaving a centra 
groove which runs through all the branches and gives tb fl 
polypidom a remarkable and characteristic appearance- 
The tubes are very prominent, and occasionally distant, ' v,1 ‘ 1 
plain round apertures. ... 
If a specimen grows in an unfavourable situation, it ffl 
sometimes be curiously distorted. I have specimens whm 
have grown in the crevices of stones in which the braucb e ® 
have been so closely pressed together that they seemed, 3 
first view, as if united into one mass; but an examination s o<j 0 
discovered the branches and the two rows of tubes. ' 
others there have been no branches and the polypidoms ha’ 
had a simple flat surface, but the peculiar leaning of 111 
tubes was present in all. It varies in length from one q» a , r j 
to half-an-inch in length; but on one occasion it attain 6 
three quarters of an inch and was the largest I ever saw. 
TUBULIPORA PHALANGEA. Encrusting; p°'?' 
pidoms divided into from two to five lobes ; tub 
divergent from a central line running through the cent r6- 
PI. xix., fig. 8. 
Hah. On stones and the wicker work of crab pots, 
from ten to twenty fathoms water, common. 
This species in its most simple state resembles a deform 6 
condition of Tvhulipora serpens, with which it has hith er ^ 
been confounded. Having examined a great number ^ 
specimens from different localities, growing under differ 6 ^ 
circumstances, I am induced, now, to consider them | 
distinct. It is encrusting, circumscribed, oval, and the o ^ 
is divided at the margins into from two lo five lobes 
festoons. Through the centre of each lobe rnns a lio® aS 
depression, from which the tubes diverge on either side ^ 
in Tubulipora serpens. The tubes are comparatively ^°g, 
and are not in contact with each other as viewed from a* 30 , 
They are numerous and arranged in perpendicular r °" |n 
each row is formed of a single series of tubes, which are 
contact with each other; each being united to the one » 
and below. This arrangement presents the appearance 
number of Pan’s pipes placed perpendicularly, the 
being separated from each other. 
