Stinging-animals.

Stinging-animals. In many different ways animals have the power of stinging. To begin with the minutest, it is likely that the trichocysts of the slipper-animalcule (Paramœcium) have some such power. Almost all the Cœlenterates, such as jellyfish and Portuguese-man-of-war, have Stinging-cells (q.v.), and in a few Turbellarians the same recur, while the dorsal papillæ of some Nudibranch Gasteropods seem to sting the mouths of animals which try to eat them. The stings of ants, bees, and wasps and some other Hymenoptera are abdominal structures, perhaps vestiges of an appendage, and they are associated with a poison-secreting gland. The poison of spiders is lodged in the chelicæræ or first pair of oral appendages. The sting of the scorpion consists of a double poison-gland lodged in the sharply pointed segment or 'telson' which lies behind the anus at the end of the tail. The sting-rays (Trygonidae) and the sting-fish or weevers (Trachinus) have no special poison-glands, but it is likely that the slime which enters into the ugly wounds caused by their sharp spines is in part the cause of the inflammation which follows. Among the Scorpaenidae the genus Synanceia has a poison-bag in each of the dorsal spines. Finally, the stinging powers of the venomous snakes are due to the modification of one of the salivary glands on each side as a poison-gland and to the adaptation of the teeth as fangs. In the poisonous Mexican lizard Heloderma an approach to a similar specialisation occurs. See also POISON.