PRESIDENTS ADDRESS. 
133 
I have indicated above a few only of the observations made by 
Messrs. Gamble and Keeble. The subject is one of considerable 
complexity, and there are many points involved which have not yet 
received any satisfactory explanation. The object of the nocturnal 
blue colour, for instance, is at present obscure, although the authors 
of the memoir suggest as a possibility that it may be “ a nightly 
reversion to the blue-green colour so characteristic of pelagic 
animals,” or possibly a means of adaptation to the surroundings 
at night. It is suggested that the brilliant red colours recorded in 
deep-sea Crustacea may be quite different from the natural colours. 
Abyssal life is associated with conditions of darkness, and it is 
possible that the red colour is, in some cases at least, merely one 
which is assumed during the passage to daylight of an animal which 
normally resembles the nocturnal Hippalyte in its coloration. The 
account of this species is of interest not merely on account of the 
facts recorded with regard to a very complex subject, but as directing 
attention to the need for further investigations on the coloration of 
marine animals. 
I may perhaps be excused for making a few references to the 
Polyzoa, the group of animals in which I have taken an especial 
interest. Although but little attention has been given to these 
animals in Norfolk, I have no doubt that a proper search would 
result in the discovery of a considerable proportion of the British 
fresh-water forms within the limits of our own county. Magnificent 
colonies of Cnstatella and Plumafella are common on the leaves 
and leaf-stems of Water-lilies at Cringleford. The former animal 
is almost unique in being a colonial animal which is endowed with 
the power of moving from one place to another in a Slug-like 
manner. The Phylactolaematn, to which most of the fresh-water 
genera belong, are peculiar in developing a remarkable form of 
reproductive body known as a “ statoblast,” and usually regarded 
as a special form of internal bud. These structures possess 
a chitinous biconvex shell, surrounded by an “ annulus ” of air-cells. 
After the conclusion of the summer, at which period the colonies 
die down, the statoblasts are set free, and float to the surface of the 
water. One object which is thereby attained is no doubt the 
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