Characteristics of the Polyzoa--Details of Structure according to Allman--Plumatella repens--Its Great Beauty under proper Illumination--Its Tentacles and their Cilia--The Mouth and its Guard or Epistome--Intestinal Tube--How it swallowed a Rotifer, and what happened--Curiosities of Digestion--Are the Tentacles capable of Stinging?--Resting Eggs, or "Statoblasts"--Tube of Plumatella--Its Muscular Fibres--Physiological Importance of their Structure CHAPTER XII. DECEMBER. Microscopic Hunting in Winter--Water-Bears, or Tardigrada--Their Comical Behaviour--Mode of viewing them--Singular Gizzard--Wenham's Compressorium--Achromatic Condenser--Mouth of the Water-Bear--Water-Bears' Exposure to Heat--Soluble Albumen--Physiological and Chemical Reasons why they are not killed by Heating or Drying--The Trachelius ovum--Mode of Swimming--Method of Viewing--By Dark-ground Illumination--Curious Digestive Tube with Branches--Multiplication by Division--Change of Form immediately following this Process--subsequent Appearances CHAPTER XIII. CONCLUSION.--Remarks on Classification, &c. MARVELS OF POND-LIFE. CHAPTER I. PLAIN HINTS ON MICROSCOPES AND THEIR MANAGEMENT. Powers that are most serviceable--Estimated by focal length--Length of body of microscope and its effects--Popular errors about great magnification--Modes of stating magnified power--Use of an "Erector"--Power of various objectives with different eye-pieces--Examination of surface markings--Methods of illumination--Direct and oblique light--Stage aperture--Dark ground illumination--Mode of softening light--Microscope lamps--Care of the eyes.