. The biology of marine animals. Marine animals; Physiology, Comparative. SKELETONS, SHELTERS AND SPECIAL DEFENCES 667 pressure on the glands causes venom to be forced into the wound. The poison of the stonefish is excruciatingly painful and sometimes fatal. More complex is the poison apparatus of the toadfish Thalassophryne. In this animal the two spines of the first dorsal fin are hollow, and the base of each spine bears a special poison gland leading into the duct. In other toad- fishes poison spines and glands also occur on the operculum (34, 118, 133). The poisonous spines just described
. The biology of marine animals. Marine animals; Physiology, Comparative. SKELETONS, SHELTERS AND SPECIAL DEFENCES 667 pressure on the glands causes venom to be forced into the wound. The poison of the stonefish is excruciatingly painful and sometimes fatal. More complex is the poison apparatus of the toadfish Thalassophryne. In this animal the two spines of the first dorsal fin are hollow, and the base of each spine bears a special poison gland leading into the duct. In other toad- fishes poison spines and glands also occur on the operculum (34, 118, 133). The poisonous spines just described in teleosts are employed in defence. The actual release of poison does not appear to be under control of the animal. In experiments with venoms of sting-rays, chimaeroids and weever- fish, it has been established that extracts of the poison glands cause sick-. Fig. Stonefish Synanceichthys verrucosus Dissected to show the Poison Glands on the Dorsal Spines. (From Whitley (133).) ness and death of test animals (fish, amphibians, reptiles and mammals). An antivenomous serum has actually been prepared against weever-fish venom. Several principles are involved in these fish poisons, including haemolytic and neurotoxic factors. Sting-ray toxin (Urobatis), in sufficient concentration, causes vasoconstriction and cardiac arrest in small mam- mals. There appears to be a direct effect on the pacemaker of the heart. The poison of the weever-fish also has a deleterious effect upon leucocytes, thus opening the way to secondary infections (34, 48, 51, 113). REFERENCES 1. Abbott, B. C. and Ballantine, D., "The toxin from Gymnodinium venereum Ballantine," /. Mar. Biol. Ass. , 36, 169 (1957). ' \a. Andrews, E. A., "Shell repair by the snail, Neritina" J. Exp. Zool., 70, 70 (1935). 2. Berrill, N. J., "The polymorphic transformations of Obelia," Quart. J. Micr. ScL, 90, 235 (1949). 3. Berrill, N. J., The Timicata: with an account of the British species (L
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