LIMNOCNIDA TANGANIOE. 
103 
of the fact that some of the observations on which his theories 
were based have been proved to be erroneous. 
The late appearance of the manubrium in Limnocnida is 
obviously a secondary feature, connected no doubt with the 
comparatively small dimensions of this organ in the adult. 
8. Summary. 
(1) The stinging-cells on the tentacles of Limnocnida 
are not developed in situ but in the ectoderm of the 
“nettle-ring/* whence they migrate to the tentacular batteries. 
The “ nettle-ring 99 is to be regarded merely as the factory 
and storage-place of these stinging-cells, and is not itself a 
functional nematocyst battery. 
(2) Limnocnida possesses a well-developed, double nerve- 
ring at the base of the velum, it is similar in most respects to 
that of Limnocodium and of other medusae. 
(3) The manubrium is undoubtedly functional as a diges- 
tive organ. The gland-cells and digestive cells are restricted 
to the more proximal regions, the oral endoderm being 
characterised by the presence of an unusually large number 
of mucus-secreting goblet-cells. 
(4) The development of the medusa-buds presents several 
interesting features, some of which are undoubtedly primitive. 
As originally described by Gunther, the entocodon is formed 
by simple invagination ; this causes the endodermal walls of 
the bud to assume the shape of a double- walled cup, which, 
almost simultaneously with its formation, becomes constricted 
at the interradii, leaving four large perradial pouches of 
endoderm, which give rise to the radial canals of the adult 
medusa. The manubrium appears very late as a rounded boss 
projecting into the umbrella cavity. 
Bibliography. 
A complete bibliography of Limnocnida tanganicae up to 1907 
will be found in E. T. Browne's memoir in the * Budgett Memorial 
Volume ’ (3). 
