Mummery on the Development of Tuhularia indivisa. 2y 
ing link between the stalk and the enclosed embryo, and has 
been denominated the placental column. The pedicle, attach- 
ing the capsules to the stalk, having now become much smaller 
in proportion, the stalk, with its capsules, presents the appear- 
ance of a bunch of grapes. Sir John Dalyell declares his in- 
ability to discover the ascending and descending currents con- 
veying granular matter, which have been observed in the stem 
of Tubularia by several naturalists. In addition to these, how- 
ever, I have distinctly noticed similar, though not equally ener- 
getic currents, in the stem supporting the reproductive gem- 
mules. 
The writer just named appears to have never detected more 
than one embryo in each cyst, but in some specimens I have 
found each cyst in the group to contain two, and occasionally 
even three embryos, distinctly perceptible through the sides of 
the cyst, which is sometimes quite transparent. 
While some clusters are fast approaching maturity, others, 
attached to the same ovary, are still in the very earliest stages 
of growth. 
As the contents of the capsules at length arrive at maturity, 
a bright red spot (which for some weeks past had become per- 
ceptible at the apex of the capsule) is observed slowly to 
expand in a quadrangular form, presenting the appearance 
shown in fig. 3, PI. IV. 
The basal extremity of the nascent animal is now seen 
slowly emerging, — the drawing (in the particular instance 
illustrated) exhibiting the progress of development at intervals 
of an hour, commencing at 8 30 p.m., and concluding at 
1 30 A.M., when the process of extrication was complete. 
The extremity which will form the future point of attachment 
in the fixed state of the young animal is always presented 
towards the aperture of the capsule, which appears to be 
dilated solely by the efforts of the animal. 
Slowly it emerges, withdrawing its tentacles in succession, 
until it has set itself free, when it crawls slowly upon the 
bottom of the vessel containing it, elevating itself on the 
extremities of its eight tentacles. 
After a period of time, varying from one to four days, the 
animal (which, in its free condition, has never been remark- 
able for activity), having selected a suitable stone, or the 
surface of an old polypidon, reverses its position, and, with 
the mouth upwards, now attaches itself by the opposite ex- 
tremity, and remains rooted fast for life. 
In every instance that has come under my notice, the first 
animal that escapes is of an ellipsoidal form, not very greatly 
