MR. H. E. HURRELL ON THE POLYZOA IN NORFOLK WATERS. 201 
dyke leading to the Surlingham Broad, and have made 
a single haul that would have filled an ordinary-sized 
pail. Strange to say, I have only found two other habitats 
for this polyzoon apart from the district I originally referred 
to, viz. : — from Postwick to Rockland in the river Yare, 
including the cuttings and dykes en route. These two 
places singularly enough are a ditch flanking the North 
Denes at Yarmouth, which is under the influence of the blown 
sands from the sea-shore, and a small lake at Burgh Castle, 
about 3| miles out to the south-west of the town. There 
can be no finer sight than the spread of its tentacles as they 
are seen emerging from the coenoecium, and with com- 
paratively high magnification the action of the cilia along 
the tentacles give one of the finest examples of the way in 
which all this class of animals form vortices in the water to 
bring food particles within the range of their mouths. There 
are many features connected with this polyzoon that would 
be well worth a paper devoted to its description alone, but 
as that is not my object I must forbear. There is one thing 
I would like to point out in connection with it, and that is the 
somewhat doubtful information we have as to the periods when 
the statoblasts are formed. I have found specimens at all 
times of the year with the statoblasts fully formed, taking 
a range of say five years, but have not yet been able to deter- 
mine whether there is a regular season for them. Lophopus 
can endure cold better than great heat, and is always in 
better condition before and after the height of summer, — 
at least, that is my experience, 
Plumatellid^:. 
The genus containing the largest number of species is 
comprised in the Plumatellidae, of which as many as nine 
English forms have been already described, although it is 
likely that the differentiation of some of them is due rather to 
the conditions and surroundings of the animal than any real 
difference in structure. The principal species is undoubtedly 
repens, and is found almost everywhere where there is plenty 
of well oxygenated water and a liberal supply of food. 
