59 
septum, however, cannot always be demonstrated, and, in 
some cases at least, appears to be incomplete. 
Most of the polypides are attached laterally to the rod by 
means of their funiculus, but ultimately the rod ends by 
giving support to a terminal polypide similarly attached to it. 
The tubes a, a, a, from which the polypides emerge, are of the 
same diameter as that of the rest of the coencecium, of which, 
indeed, they are simple continuations. At their commence- 
ment they are adherent like the other portions, but they 
soon become free, and then ascend, more or less vertically, 
from the surface of attachment. They are beautifully annu- 
lated, the annulation being due to circular ridges, into which 
the outer surface of the ectocyst is raised, and which follow 
one another at short intervals, and with perfect regularity. 
The inner surface of the tube is quite smooth. The annu- 
lated condition may occasionally be traced for a little dis- 
tance backwards on the adherent portion, while the rest of 
the adherent portion exhibits, under proper illumination, a 
peculiar marking in the form of slightly elevated and very 
faintly marked ridges (fig. 4), which are seen upon the upper 
side of the tube, and wliih here take an oblique course from 
the margins towards the centre, till each is interrupted by 
meeting the corresponding ridge from the opposite side. 
The whole of the tubular cocncccium, both the free and the 
adherent portion, is perfectly hyalline, so that the adherent 
portion, which has not the distinct annulation of the free 
tubes to assist in rendering it visible, is liable to be over- 
looked under too low a power and with insufficient illumina- 
tion. Under such circumstances the polyzoon presents an 
anomalous appearance, the dark opaque central rod, with its 
appended polypides and the free annulated tube being the 
only parts visible. 
The polypides are hippocrepian. They are, indeed, as 
completely so as in Plumatella or any other typical hippo- 
crepian polyzoon. My specimens, however, being such only 
as had been for several months immersed in strong spirits, 
do not allow me to speak with certainty as to the existence 
of the calyeiform membrane which connects the bases of the 
tentacles in all the other known typical hippocrepians. 
Neither can I say whether an epistome — another striking 
and important feature in all hitherto known hippocrepian 
Polyzoa — is or is not present in Rhabdofleura. These 
and some other points of structure must remain undeter- 
mined until the examination of living specimens shall afford 
an opportunity of seeing the soft parts in an unaltered con- 
dition, and of witnessing the natural evolution of the poly'- 
