Role of the gills in osmotic regulation in the crayfish Astacus leptodactylus esch.

Abstract

• 1.

  1. The amount of urine produced by the crayfish Astacus leptodactylus in fresh water amounts to 4·6 per cent of its fresh weight/24 hr.

• 2.

  2. The amount of water taken in by the gills in the same medium is 4·0 per cent.

• 3.

  3. About 10 per cent of the water taken in penetrates through a surface other than the gills.

• 4.

  4. The area of the fully developed gills is 5·5 cm²/g fresh wt. and the surface of the gill processes amounts to 5·1 cm²/g fresh wt.

• 5.

  5. Water permeability constant calculated for the gill processes amounts to 0·12 μ/sec.