VENOMS IN THE ANIMAL SERIES 273 
by contact with the anemones, they should be advised to cover 
their bodies with a layer of grease, a simple artifice which con- 
stitutes an efficient protection. 
B.—EcHINODERMS. 
The Echinoidea (Sea-urchins) are provided with soft prehensile 
organs, the pedicellarie, of which four kinds are distinguished : 
gvemmiform, 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 
pedicellariz alone are toxic. 
From this point of view various species of sea-urchins, Strongy- 
locentrotus lividus, Arbacia equituberculata, Spherechinus granu- 
laris and Spatangus purpureus, have recently been studied by 
V. Henri and Mdlle. Kayalof.! 
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 pedi- 
cellariæ of Strongylocentrotus lividus. 
The holothurians, star-fish, and frogs proved immune. 
In the case of rabbits weighing 14 kilogrammes, 40 pedicellariæ 
of Spherechinus granularis, pounded up in 1 c.c. of water, produce 
death by asphyxia and general paralysis in from two to three 
minutes. The heart continues to beat after respiration has ceased. 
For lizards and fishes the toxic dose is the same as for the crab. 
The cuttle-fish is paralysed and killed in two hours by 50 
pedicellariæ. 
! Comptes rendus de la Société de Biologie, May 19, 1906. 
18 
