552 Records of the Indian Museum. [VoL. XI, 
with that of the hydranth, and asa slight ridge well furnished 
with nematocysts surrounds the opening, it is possible that here is 
foreshadowed the adult mouth. 
Serial sections reveal the fact that at the place of origin of a 
bud considerable activity is shown by the endoderm of the hy- 
dranth, which is crowded with finely granular protoplasm and 
engulfed food particles. These features are carried into the endo- 
derm of the developing bud, the cells of the proximal portions of 
which contain much secretory and food material. The mesogloea 
of the bud is somewhat less developed than that of the hydranth, 
and the ectoderm is remarkable for the regularity and high, narrow 
palisade-like structure of the cells at both extremities. These con- 
tain spherical nuclei similar in size to those of the endoderm (3, in 
diameter), and many nematocysts of both types undergoing de- 
velopment. As the bud increases in size some of these approach 
the surface of the ectoderm and lie in position for functioning, 
although in none of the buds, attached or free, are cnidocils pre- 
sent. An extremely thin cuticle is excreted by the ectoderm. I 
have seen no indication of the presence of an external coat of cilia. 
The neck joining bud to hydranth is formed of ectoderm, 
mesogloea and endoderm, and in spite of the narrowness due to 
increasing constriction there is no sign that rupture is preceded 
by the disappearance of the endoderm, as in the case of the hy- 
droid of Gonionemus murbachii (see p. 561), or of the ectoderm, 
as in the cases of the basal bulb described below, or of the sporo- 
sac buds of species of Dicoryne.' 
Longitudinal fission. 
In a single specimen longitudinal fission appears to be in pro- 
gress (see pl. xxx, fig. 3). From the neighbourhood of the ten- 
tacle-zone of a well-developed hydranth with in all eleven tentacles 
a secondary hypostome branches out as if due to the division of 
the original hypostome. Both hypostomes are normal in character 
and the mouth of each is connected in the usual way with the 
common coelenteron of the hydranth. The endoderm layer be- 
tween one hypostome and the other is of uniform thinness and 
regularity, and shows no prolongations or other abnormalities in 
the neighbourhood of the fission angle. ‘The smaller hypostome 
has appropriated some of the tentacles of the original hydranth, 
and new smaller ones are arising at its base. Whether this pro- 
cess is to be reckoned as a normal mode of reproduction or whether 
the instance described is rather an abnormal case of budding or 
duplication than an example of true fission, I have no means of 
deciding. 
The Basal Bulb. 
Reference has already been made to the significance of a 
structure which I have termed the basal bulb. To judge by the 
! See Ashworth and Ritchie, 1915. 
