668 
MR. F. BALFOUR BROWNE ON A 
and two each in Wroxham and Ranworth. With regard to the 
fourteen secondary sub-districts, as many as fifty-three species were 
not recorded last season from districts where they have previously 
been found, but of these, records of twenty-seven were wanting 
from Potter Heigham and nine from Ludham, two districts which 
had very little attention paid them last year. I do not propose to 
refer to all these species which have apparently changed their 
locality, but reference to one or two examples will suffice. 
In the summer of 1900 Diaplianosoma brachyurum was abundant 
at Calthorpe, but it was absent last summer. 
In June, 1902, Bosmina longirostris was quite common at 
Calthorpe, whereas last summer it was not to be found. 
Diaptomus gracilis did not occur at Wroxham last season, 
although previously recorded from there. 
Ceriodapnia laticaudata, Chydorus globosus, Eurycercuslamellatus , 
Cyclops fuscus, and Nitocra hibernica — five species previously 
taken in the Heigham sub-district, were not found there last season. 
Now all these apparent changes in local distribution may be the 
result of insufficient investigation, but Mr. Gurney has told you of 
his work which he carried on throughout the season, and although 
possibly his lists are not complete, I do not think, that this 
explanation will entirely cover the case. I hope at the end of 
the present year he will be able to compare his results with last 
year’s work and perhaps show further changes in the local 
distribution of the Entomostraca. 
Mr. Soar has done some work upon the Hydrachnids of the 
Norfolk Broads, but his records up to the present time are few in 
number. Out of the list of forty-six species which he has sent me 
he has found thirty-one in the neighbourhood of Potter Heigham. 
I hope, however, at the end of the present year he will have 
a fairly complete list of the local distribution, at any rate, in the 
ten primary sub-districts. 
I have, during the past season, been working at the distribution 
of the Dragon-flies, and the result, so far as the Zygopterids — 
(thin-bodied, weak-flying species) — are concerned, is decidedly 
encouraging. 
As you probably know, the Dragon-fly egg is laid in the water, 
either directly upon some solid object under the surface, or dropped 
at random and allowed to sink. From the egg, after a few weeks, 
emerges what is known as a nymph, which moults several times 
