1148 JOURNAL, BOMBAY NATURAL HIST. SOCIETY, Vol. XXVlll. 
Fission. — An instance of vertical fission was witnessed on the 26th August, 
1920. Fission was more or less complete and the two j)olyps were still united 
by the basal j)art of the column. One had five tentacles and tlie other four. 
The contraction and e.xpansion of the column and tentacles of the polyps were 
independent. The gastro-vasculai' ca^•ities were continuous and small jmrticles 
were seen passing througli the fluid from the gastral cavity of one into that of 
the other. The ectoderm and endodenn were distinct, and at the base of the 
polyps were observed two endodcrmal prominences. The ectoderm in this 
region was slightly depressed. (See Fig. 3.) 
On the following day an endodcrmal wall Avas completely formed cutting off 
the gastro-vascular cavity of one polyp from that of the other. The ectodermal 
depression was invaginated. On the third day the ectoderm of the basal disc 
was formed and the polyps were sticking to each other by a secretion of mucus. 
The same evening they were observed to have separated. The difference in 
the number of tentacles of the two polyps was still maintained. 
Though several polyps were reared for over two months this was the only 
instance of vertical fission observed. 
In his account of Hydra in the Memoirs of the A siatic Society of Bengal, I, p. 344, 
1906, Dr. Annandale states that he has only seen throe instances of vertical fission. 
Apparently this mode of reproduction is very rare. 
Budding. — Several individuals bearing two or three buds were seen during 
the earlier part of August. l\Iost of the buds were in a fairly advanced state 
Avdth, as a rule, the same number of tentacles as in the parent polyp. The 
lower half of the column was slender and transparent, and as a result of swell- 
ings the upper half was moniliform (Fig. I). Usually the buds were 
confined to a small zone about the middle of the column ; and it Avas remark- 
able that the column beloAv this zone did not present a moniliform appeaj’ance. 
This phenomenon Avas noticeable in the budding indiA’iduals only. That the 
SAvellings are different from buds is suggested by the fact that they sometimes 
disappear and reappear in the same place. The entire gastro- v-ascnlar cavity 
is clear, and any food particle too large for it can at once be seen. SeAmral in- 
dividuals AAdth the SAvellings Avere examined, and in none of them Avere they the 
result of distension by food particles or other foreign matter. 
The budding polyps Avere generally found attached to the bottom and sides 
of the glass- jar, and to the underside of weeds. 
The polyps attached to the sides lay usually inclined upside doAV'n Avith the 
tentacles fully expanded and hanging pendulously. A horizontal and rarely 
an erect position Avas hoAA^ever assumed by some indiAuduals. 
In the “ Fauna ” volume on Fresh-Avater Hydroids, Dr. Annandale states 
that he has never seen a bud giving rise to buds while attached to the parent 
hydra. I have seen an instance of this phenomenon on a single occasion (August 
18, 1920). This polyp Avas found at the bottom of the jar. It aaus difficult 
to make out the order in Avhich the buds had arisen. Tliere AAere tAvo fairly 
Avell developed buds, one Avith five tentacles, and the other Avith six. The for- 
mer had one bud and the latter tAVO (Fig. 2). It may be suggested that the 
first parent polyp underwent A'eitical fission for some distance doAvn the column, 
Avhen budding started precauciously on each of the daughter polyps. There Avas 
hoAvever no clear evidence to shoAV that the colony formed as entirely due to 
budding or to vertical fission and budding. This branching hydra AA-as unfortun- 
ately devoured by a dragon-fly larva a foAV days later, and no further observation 
could be made on it. 
Branching in II . oligactis Avas noticed by Baini Prashad in Lahore.* 
Spermaries. — From about the last Aveek of August upto the 4th September, 
several polyps bore spermaries. Subsequent to this date sexual activity gra- 
See Journ., As. S.ic., Bengal, (N. H. 8.) XII, p. 143 (19] t> 
