NOTES. 
ORIGINAL AND SELECTED. 
2S9 
(Water-fleas) were by no means very common as, speaking gener¬ 
ally, they were only produced for two comparatively short 
periods each year. In the case of species living in small ponds 
liable to be dried up in summer, males and ephippial females 
usually occurred in May or June, whereas in larger ponds and 
lakes the sexual period occurred normally in the autumn. It 
was most unusual to obtain males in mid-winter, but in this 
particular instance the artificial conditions under which the 
animals were living, namely in a small bottle in an ordinary 
room, may have been responsible for the production of the 
specimen shown.—D. J. Scourfield, F.R.M.S., F.Z.S., Leyton- 
stone. 
Dalyellia diadema, Hofsten ; a rare Turbellarian Worm 
new to Britain.—A note in the present volume of the Essex 
Naturalist ( ante p. 142) records the occurrence of an in¬ 
teresting Turbellarian Worm, Dalyellia viridis, in a pond at 
Chigwell Row. Some water and aquatic vegetation were taken 
from the same pond in June 1912, and on allowing this to stand 
for a few days four or five specimens of a tiny species of Dalyellia 
were discovered. Notes and sketches of the characters were 
taken at the time and three specimens were preserved, but 
nearly a year elapsed before they were identified as Dalyellia 
diadema , Hofsten. Subsequent search in April 1913, resulted 
in the capture of one specimen, but this was sufficient to establish 
the identity beyond all doubt. 
D. diadema was first described by Dr. Nilo Von Hofsten 
[Zeitschrijt fur wissenschajtliche Zoologie Bd Lxxxv (1907)], 
who found it in the Bernese Alps. It is about 1 mm. (-A inch) 
in length. The animal when swimming is spindle-shaped, the 
anterior being blunter than the posterior region. The length 
is about four times the breadth. The specimens obtained by 
the writer each contained a single egg. In D. viridis the 
number of eggs carried in the body cavity may exceed forty. 
D. diadema is almost colourless, there being no signs of 
“ zoochlorellae ” or algal cells. 
Dr. Hofsten in a letter to the writer stated that he has 
not seen any specimens of D. diadema since 1907, and has not 
found any records of their occurrence since. Truly as Mr. 
Whittaker remarked “ Even a worm will turn (up)—if searched 
for.”—H. Whitehead, B.Sc., Essex Museum of Natural History , 
Stratford. 
