268 HISTORY OF BRITISH CRUSTACEA. 
assume a red colour, it has been said that they have com- 
municated a bloody hue to water. Dr. Baird has observed 
large patches of water of a ruddy hue, and ascertained the 
cause to be an immense number of the Daphnia jpulex ; 
“the myriads necessary to produce this effect are really 
astonishing, and it is extremely interesting to watch their 
motions. On a sunshiny day, in a large pond, a streak of 
red, a foot broad, and ten or twelve yards in length, will 
suddenly appear in a particular spot, and this belt may be 
seen rapidly changing its position, and in a very short time 
wheel completely round the pond. Should the mass come 
near enough the edge to allow the shadow of the observer 
to fall upon them, or should a dark cloud suddenly ob- 
scure the sun, the whole body immediately disappears, 
rising to the surface again when they have reached beyond 
the shadow, or as soon as the cloud has passed over. They 
are very prolific.”* 
Subfamily Daphnina. 
Burnished with five pairs of feet ; lower antennae two- 
branched ; one branch divided into four, the other into 
three joints. 
* Baird, Brit. Entomostraca, p. 78. 
