28 POND LIFE 



tributed as the latter. Stentor Niger does not surround itself 

 with a case. Stentor Coeruleus is scarlet in colour, Stentor 

 Igneus blue. 



The stentors are the largest of the Ciliata. The colouring 

 pigment in the Blue Stentor has been named by Lancaster 

 blue stentorin. 



CHAPTER II 



AQUATIC CRUSTACEANS 



" GIVE a dog a bad name and hang him '' is very true in the 

 world in which we live, and the reader, particularly if a 

 member of the gentler sex, will probably leave this chapter 

 unread. For the flea is an animal barred from conversation. 



Its existence is ignored by those free from its presence, 

 whilst he or she chosen by the interesting little animal as a 

 food supply is belabelled as uncleanly. 



But the water-flea is no relation to " the flea we don't know." 

 It is a harmless, interesting little creature, far too busy in 

 its own sphere of life to interfere indirectly or directly with 

 the all- important man and his subordinates. 



One may notice occasionally, particularly on a warm summer 

 day, that certain parts of the pond are reddish or whitish 

 colour. This colour on closer examination will be found to 

 be the result of large numbers of water-fleas congregated in 

 that particular district. These creatures are members of 

 Cladocera, a sub-order of the Branchiopoda, a division of the 

 crustaceans, and are characterised in that their breathing organs 

 are attached to their limbs (Branchius poda = leaf-footed). 

 There are several species of water-fleas, some small, others 

 comparatively large. Some live in running water, others prefer 

 the most stagnant pool, whilst yet another species inhabits 

 water so saturated with salt that no other creature could 

 possibly live there. A few that live at a great depth or in 

 underground water are eyeless. 



The British Cladocera are divided into eight families, all 

 more or less resembling the Daphnia. 



Each little creature is surrounded by a case, known as the 

 carapace, which varies both in size and in shape in different 

 families. In some the carapace is large and entirely encloses 

 the creature ; in others it is small, and in the case of Gym- 

 nomora it is large when the creature is carrying its eggs, but 



