The poison-apparatus of _Scorpæna_ is situated in the spiny rays of the dorsal and anal fins. These rays are enveloped in the inter-radial membrane, which forms a sheath for them, and are scored with a double cannelure. At the bottom of these grooves are the secreting cells, which are elongate, pressed one against the other, and supported at the base by a highly vascular substratum of connective tissue. The venom flows out between the layer of cells and the ensheathing membrane, which is capable of being pushed slightly back as the result of the penetration of the spine into the tissues, and then exerts pressure upon the reservoir. The latter is formed by the distension of the sheath under the pressure of the secreted liquid. [Illustration: FIG. 105.--_Pterois artemata_ (East Coast of Africa, Indian and Tropical Pacific Oceans). (After Savtschenko.)] There are twelve pairs of dorsal and three pairs of anal glands. The pairs attached to the second anal spine are, as the direct result of the size of the latter, more developed than those of the other spines. In the _Rascasse_, the opercular spines of which are greatly developed, there is a rudiment of a poison-apparatus at the bottom of the sheath formed by the skin of the gills. The species of _Pterois_ (fig. 105) are distinguished from those of _Scorpæna_ by their dorsal fins, the rays of which are very long and curved backwards, above the membrane by which they are united. They are found in the Indian and Equatorial Pacific Oceans, and are very beautiful in colour, varying from reddish-brown to bright rose. The poison-apparatus of these fishes is situated in the dorsal fin, and is precisely similar to that of _Scorpæna_. [Illustration: FIG. 106.--_Pelor filamentosum_ (Family _Triglidæ_, Mauritius).] The species of _Pelor_ (fig. 106) present greater resemblance to those of _Synanceia_, owing to their heads being crushed in in front. Their eyes stand up above the head and are very close together, which helps to give them an extremely ugly appearance. The skin is soft and spongy, and bristles with jagged fleshy shreds. Their poison-apparatus is placed in the dorsal fins, as in the case of _Scorpæna_ and _Pterois_. 2.--Trachinidæ. Genus _Trachinus_ (Weevers).--Four species of Weevers are found in European seas: the Greater Weever (_Trachinus draco_), the Lesser Weever (_T. vipera_), the Striped-headed Weever (_T. radiatus_), and the Mediterranean Spider Weever (_T. araneus_); other species are met with on the coast of Chile. Weevers possess two sets of poison-apparatus, one of which is situated on the operculum, the other at the base of the spines of the dorsal fin (fig. 107). [Illustration: FIG. 107.--_Trachinus vipera_ (Lesser Weever).]