EOI2;,| N. ANNANDALE: Fauna Symbiotica Indica, 3. 149 
resemble those of Fredericella, to which belong the only species 
hitherto described in which all of these bodies are devoid of a ring 
of air-cells. The fixed statoblasts of Plumatella, however, always 
resemble those of Fredericella, and that to a different extent in 
different species. It is probable in the present instance that the 
production of fixed statoblasts only is an adaptation correlated with 
the peculiar method of life adopted by the polyzoon. As the 
tortoises to which it is attached leave the water for purposes of 
oviposition, if not for other purposes also, it is perhaps necessary 
that the Plumatella should not altogether lose their services as 
beasts of burden at any period in its life-cycle, solid objects to 
which it can affix itself being few and far between in the mud of 
the Ganges. 
In its general appearance P. destudinicola bears a remarkable 
but of course quite superficial resemblance to certain Cheilostomes 
and Ctenostomes that encrust flat surfaces. The method of 
budding is, however, completely different, for the closely com- 
pacted parallel branches of the zoarium are produced by linear 
budding or by the production in the first instance of two divergent 
buds at the tip of a parent zooecium. Except at and near the 
centre (which is the oldest part of the zoarium) there is no 
organic connection between the different branches, which, at 
any rate near the periphery, merely lie alongside one another. In 
the older parts of the colony it is clear that the production of 
divergent buds in the position indicated has been frequent but 
that they, or rather the branches produced from them by linear 
budding, have become closely pressed together and therefore 
parallel, not apparently having the power of raising themselves 
from the basis to which they. adhere. Thus the method of bud- 
ding differs from that of such forms as Membrantpora and Hislopia 
in that lateral buds are never produced, while there is no single 
zooecium from which the branches radiate outwards as in Flustrella 
and many other encrusting forms. Indeed, it seems probable that 
each apparent colony is not really a single zoarium but rather 
the result of budding on the part of a group of statoblasts or 
embryos from each of which branches have been produced in one 
or in two directions. In Plumatella tanganytkae, although compact 
flat zoaria are often found, it is always possibie to see that their 
branching is fundamentally bilateral and probably arises from the 
fact that the two first polypides produced from a single statoblast 
or embryo have diverged from one another before fixation was 
completed. In P. testudinicola, on the other hand, each colony 
appears to have arisen from a group of separate but closely 
adjacent individuals, the branches of which have been forced to 
diverge by mutual pressure. It is, however, difficult to be quite 
sure of this without studying young growing zoaria, which I have 
not seen, as the central part of old zoaria is always in a more or 
less decayed condition. 
My specimens of the new species were taken in March, and it 
is evident that the vegetative phase of their life-cycle was practi- 
