Cf. p. [343].
See p. [423].
Howes (P.Z.S. 1893, p. 730) has described certain remarkable variations in the respiratory organs of Petromyzon and Myxine.
In certain Teleosts more or fewer of the branchial arches may lose their gills. This reduction attains its maximum in the singular Indian amphibious Fish, Amphipnous cuchia, where only the second arch has a biserial gill, the remaining arches being wholly devoid of gills (cf. p. 598).
Balfour, Comp. Embryol. ii. 1881, p. 62.