Section of a Branchial Arch of a Cod
In breathing, the mouth and gills of a fish open alternately; the water entering the mouth escapes by the opening of the gills. Shown is a section of the bronchial arch of a cod, with a pair processes supporting leaflets or plates. Labels: 1. A section of the branchial arch. 2, A pair of processes. 3, Branchial leaflets or plates. The number of leaflets in one process of the cod is about one thousand; in the salmon fourteen hundred; in the sturgeon sixteen hundred.