Cf. Boas, Morph. Jahrb. vi. 1880, p. 527, who has found the conus, but in a still more rudimentary condition, and with a single row of valvules, in Heterotis and Notopterus also.
For a general account of the Fishes of this family, cf. Boulenger, P.Z.S. 1898, p. 775, and Poissons du Bassin du Congo, p. 49 (1901), where a bibliographical index to the principal anatomical and physiological publications will be found.
Trans. Zool. Soc. xvi. 1901, p. 126.
Journ. Linn. Soc. xxvii. 1900, p. 503.
On the Anatomy, cf. Agassiz, in Spix, "Pisc. Brasil." p. 32; Hyrtl, Denkschr. Ak. Wien, viii. 1855, p. 73; Hemprich and Ehrenberg, "Symb. Phys." Zootom. pls. viii. and ix.; Bridge, P.Z.S. 1895, p. 302.