The first symptoms that supervene after contact with these Cœlenterates are an intense itching and burning sensation; a papule of a horny consistency appears at the outset at the spot at which contact took place; this is soon surrounded by a red zone, which becomes bluish and then black, and spreads to a greater or lesser extent, according to the region attacked and the virulence of the venom. After a few days the skin sloughs and leaves a deep ulcer, which suppurates in spite of antiseptic treatment. The onset of the disease is marked by a febrile attack with shivering, which is soon accompanied by cephalalgia, thirst, and pains in the back and limbs. Zervos reproduced these disorders experimentally by rubbing an anemone, held with forceps, on the shaven abdomen of a dog. In a few minutes the region affected became quite red and pruriginous; twenty-five minutes later phlyctenæ full of serum appeared; three days afterwards five abscesses of different sizes developed, while at the place where it had been touched by the venom the skin assumed a deep blue colour; on the fifth day an area 2 cm. in diameter was completely gangrenous. When ingested, anemones possess toxic properties which are well known to the sponge-fishers, for they frequently make use of them for the purpose of poisoning domestic animals. With this object they cut them up into small fragments, and mix them with bread or meat, which is given to the animals to eat; the latter die in convulsions in a few minutes. In order to preserve the divers from the harmful effects produced by contact with the anemones, they should be advised to cover their bodies with a layer of grease, a simple artifice which constitutes an efficient protection. B.--ECHINODERMS. The _Echinoidea_ (Sea-urchins) are provided with soft prehensile organs, the _pedicellariæ_, of which four kinds are distinguished: gemmiform, tridactyle, trifoliate, and ophiocephalous. These pedicellariæ contain a special venom, which causes the paralysis and death of animals into which it is injected. Uexkull, who was the first to mention it, considered that the gemmiform pedicellariæ alone are toxic. From this point of view various species of sea-urchins, _Strongylocentrotus lividus_, _Arbacia æquituberculata_, _Sphærechinus granularis_ and _Spatangus purpureus_, have recently been studied by V. Henri and Mdlle. Kayalof.[110] The pedicellariæ were removed and pounded up in sea-water, and the pulp was injected into crabs, holothurians, star-fish, cuttle-fish, frogs, lizards, and rabbits; in the case of cuttle-fish and rabbits the injection was made intravenously; in that of the other animals into the body-cavity. For crabs the lethal dose was from 20 to 30 gemmiform pedicellariæ of _Strongylocentrotus lividus_. The holothurians, star-fish, and frogs proved immune.