TUBICINELLA. _Lamarck._ Annales du Museum, tom. 1 (1802), Tab. 30,
fig. 1.
CORONULA. _De Blainville._ Dict. des Sciences Naturelles, (1824).
_Compartments six, of equal sizes; shell sub-cylindrical, wider at the
top than at the basis, belted by several large transverse ridges._
_Hab._--Southern Pacific Ocean, Western South America, New South
Wales, Cape of Good Hope; imbedded in whales, and often associated
with _Coronula balænaris_.
This genus is closely allied to Coronula, and perhaps De Blainville was
right in uniting them. But Coronula, as it now stands, is so natural
a genus, that it seems a pity that a form so entirely different in
general aspect, as Tubicinella, should be forced into it. The main
difference between these genera consists in the walls being here not
folded, in the simpler radii, and in the general shape of the shell and
of the included animal's body; but there are many other minor points
of difference. The most novel character in Tubicinella consists in
the shell being lined almost close down to the basis by the opercular
membrane. In the opercular membrane thus forming a long tube, and in
the general shape of the animal's body, we shall presently see that
Tubicinella is closely related to Xenobalanus. In numerous other
respects Tubicinella is almost equally allied to the latter genus,
to Platylepas, and to Coronula. Finally, several points of structure
indicate that Tubicinella may be considered as a Coronula, with the
shell much simplified in structure.