THE SWIMBLADDER AS A HYDROSTATIC ORGAN 



73 



The gas-gland 

 In parallel with their retia, the gas-glands of bathypelagic teleosts are relatively large compared with 

 those of shallow- water species. Some attention has already been drawn to this (Marshall, 1950, 

 1954; Jones and Marshall, 1953). Here a closer comparison will be made between various epipelagic 



Text-fig. 36. Swimbladders of some epipelagic and bathypelagic fishes, showing the relative developments of the retia 

 mirabilia and gas-glands. Epipelagic species: (a, a') Cypsilitrus cyanopterus; (b, b', b") Danichthys rondektii; (c, c') Exocoetus 

 volitans; (d, d') Petatichthys capensis; (e, e') Hyporhamphus sp. Bathypelagic species: (f) Vinciguerria attenuata; (g) Argyro- 

 pelecus aculeatus; (h) Myctophum punctatum; (j) Chiasmodon niger; (k) Melamphaes megalops. Gas-gland dotted; retia, with 

 striations along the major axes. In a', b', b", c', d' and e' part or the whole of the gas-secreting complex is shown enlarged. 

 (A, xo-38; a', x 10; B, xo-6; b', x 5; b", 2-5; C, x 1 ; c', x 5; D, x i; d', x 5; e, x i ; e', X4; F, x 10; G, x 10; H, x 38; J, x6; 

 K, x 5 .) 



