M

1. Magnesium, 175

2. Mammalia:

   1. reproduction, 326

   2. synopsis, 313

3. Manganese, 184

   1. in red clay, 1029, 1030

   2. nodules and concretions, 952, 1028

4. Mechanical analysis of sediments, 958, 970

5. Mediterranean Sea:

   1. bottom topography, 34

   2. currents, 647, 648

   3. formation of bottom water, 645

   4. oxygen content, 648–650

   5. plant nutrients, 245

   6. water masses, 643–646

6. Mediterranean Water, spreading of, 670, 685, 686, 745

7. Medusae:

   1. biological studies on, 320, 820

   2. reproduction, 320

   3. synopsis, 306

8. Meroplankton (see Zooplankton, temporary)

9. Messengers, 354

10. Meter wheel, 338

11. Micro-plants, significance of, 883–884

12. Migrations:

    1. eel, 811, 861–862

    2. from land to sea, 283, 302

    3. from sea to land, 284

    4. salmon, 811

    5. vertical, 835–839

    6. whales, 811, 905

13. Mixing length, 472

    1. near a boundary surface, 479

14. Mollusca:

    1. reproduction of, 324

    2. synopsis of, 310–311

15. Momentum, transport of, 472, 473

16. Mucus feeding, 889, 894

17. Mud flows, 960