On Apus: its rediscovery in Britain, nomenclature and habits



  • 1Until 1948 Triops cancriformis (Bosc) had only been recorded five times in Britain, namely in 1738, 1816, about 1830, in 1907 and 1935. It has been found again in 1947 and 1948 in the same Hampshire pool from which it was recorded in 1935; it seems thus to be endemie.
  • 2A historical account is given of the two best-known species of Notostraca, Triops cancriformis (Bosc) and Lepidurus apus (L.).
  • 3It is proposed to suppress the Linnaean genus Monoculus.
  • 4In Triops, as in Daphnia, the amount of haemoglobin in the blood is inversely proportional to the oxygen content of the water in which the animal lives.
  • 5Triops swims up to the water surface in response to a stimulus of oxygen deficiency more often when its blood is poor than when it is rich in haemoglobin.
  • 6The paired eyes of Triops are in continual movement, like the eye of Daphnia and the eyes of crayfish. The trembling movement may assist the animals to perceive objects in the surroundings.