284
FINDLAY E. RUSSELL
the same technique used in Saipan, where the fishermen wear goggles to
protect their eyes from the irritating substances of these animals.
According to Nigrelli and Jakowska (1960) at least thirty species
belonging to four of the five orders of Holothuroidea are toxic. Some
toxic species [ Thelenota ananas (Jaeger), Stichopus variegatus Semper,
Holothuria atra (Jaeger) and H . aziolaga H. L. Clark] are highly
esteemed as food in the Orient.
A. Venom apparatus
1. Asteroidea
The starfishes have simple thorny spines of calcium carbonate
in the form of calcite intermingled with organic substances. The
spines are held erect by a number of muscles. Specialized glandular
tissue is embedded in the calcite and is capable of secreting a toxin
which can be discharged into the water or perhaps directly into the
skin. The stimulus for the discharge of the poison and the mechanism
by which it is released are not known.
2. Echinoidea
In the regular sea urchins the body is globular and radially symmetrical. It is enclosed in a hard calcite shell from which calcareous
spines and pedicellariae arise. The spines may be straight and pointed,
curved, flat-topped, club-shaped (bearing poison glands), oar-shaped,
umbrella-shaped, thorny, fan-shaped or hooked, and may vary in
length from less than 1 mm to over 30 cm. Each spine is borne on a
tubercle of the thecal plate, to the rim of which the spine muscles am
attached. The spines serve in locomotion, protection, digging, feeding,
producing currents and harboring larvae; certain of them bear
" poison " glands.
" Poisonous spines " are most highly developed in the family
Echinothuridae, particularly in the genus Asthenosoma. The smaller
spines in Asthenosoma varium Grube terminate in specialized poison
organs containing a gland, which empties its toxin through the hollow
spine tip into the wound produced by the spine. In other echinothurids,
such as in Araeosoma thetidis (H. L. Clark), these secondary spines also
terminate in poison organs but they are much less specialized than in
Asthenosomu varium. The poison organs may rupture as the spine enters
the skin, thereby discharging their toxin directly into the wound. I n
Asthenosoma the spines of the aboral side are enclosed in a thickened,
ringed and pigmented bag of skin which is thought to contain poison
glands. In Phormosoma the primary spines on the oral side are also
thought to contain poison glands (Mortensen, 1929). In Diadematidae
FINDLAY E. RUSSELL
the same technique used in Saipan, where the fishermen wear goggles to
protect their eyes from the irritating substances of these animals.
According to Nigrelli and Jakowska (1960) at least thirty species
belonging to four of the five orders of Holothuroidea are toxic. Some
toxic species [ Thelenota ananas (Jaeger), Stichopus variegatus Semper,
Holothuria atra (Jaeger) and H . aziolaga H. L. Clark] are highly
esteemed as food in the Orient.
A. Venom apparatus
1. Asteroidea
The starfishes have simple thorny spines of calcium carbonate
in the form of calcite intermingled with organic substances. The
spines are held erect by a number of muscles. Specialized glandular
tissue is embedded in the calcite and is capable of secreting a toxin
which can be discharged into the water or perhaps directly into the
skin. The stimulus for the discharge of the poison and the mechanism
by which it is released are not known.
2. Echinoidea
In the regular sea urchins the body is globular and radially symmetrical. It is enclosed in a hard calcite shell from which calcareous
spines and pedicellariae arise. The spines may be straight and pointed,
curved, flat-topped, club-shaped (bearing poison glands), oar-shaped,
umbrella-shaped, thorny, fan-shaped or hooked, and may vary in
length from less than 1 mm to over 30 cm. Each spine is borne on a
tubercle of the thecal plate, to the rim of which the spine muscles am
attached. The spines serve in locomotion, protection, digging, feeding,
producing currents and harboring larvae; certain of them bear
" poison " glands.
" Poisonous spines " are most highly developed in the family
Echinothuridae, particularly in the genus Asthenosoma. The smaller
spines in Asthenosoma varium Grube terminate in specialized poison
organs containing a gland, which empties its toxin through the hollow
spine tip into the wound produced by the spine. In other echinothurids,
such as in Araeosoma thetidis (H. L. Clark), these secondary spines also
terminate in poison organs but they are much less specialized than in
Asthenosomu varium. The poison organs may rupture as the spine enters
the skin, thereby discharging their toxin directly into the wound. I n
Asthenosoma the spines of the aboral side are enclosed in a thickened,
ringed and pigmented bag of skin which is thought to contain poison
glands. In Phormosoma the primary spines on the oral side are also
thought to contain poison glands (Mortensen, 1929). In Diadematidae