A GUIDE TO THE STUDY OF FRESH-WATER BIOLOGY. By James G. Needham and Paul R. Needham.

(ND) 1938 4th edition revised and enlarged. 8vo stapled paperback (141 x 217mm). Ppii,89. B/w line illlustrations. Sage green boards. Constable and Company Ltd slip tipped to title-page.

"Fifth edition, revised and enlarged." The purpose of this book is to "facilitate the recognition of fresh-water organisms both in the field and laboratory [using] keys, tables, and figures illustrating mostly genera and in a few cases, species. Only organisms commonly found in fresh waters are included. Inhabitants of salt, brackish, and alkaline waters are omitted. Vascular plants are also omitted. Generic names are applied in an inclusive sense to groups or species that a beginner may be able to recognize by external differences. ...Keys to the most common forms [of fish] caught by anglers are presented along with four new plates covering both structures and some 65 kinds. New plates of protozoans, water bugs, caddis-worm houses, and aquatic beetles are also presented. New materials have been added on the following items: caring for field collections, methods of taking quantitative stream and lake bottom samples, the quantitative distribution and abundance of stream dwelling organisms, methods of making analyses of water for oxygen, carbon dioxide, alkalinities, and the determination of pH values."