Outstanding texts in the biological sciences

Practical Invertebrate AnatomyBy W. S. Bullough

A complete laboratory reference, this book describes more than 100 invertebratescommonly examined by zoology students. Each description is prefaced by anaccount of the distribution, habitat and mode of life of the genus. Notes on un-usual organic structures are included, together with details of classification. Aseries of 168 drawings, directly labelled, provide clear and precise illustration.Appendices describe the methods of culture, killing, fixing and preserving speci-mens. Published in June. $4.50

Biology of the VertebratesThird Edition

By Walter and SaylesIn making the revision, Dr. Sayles has kept the flavor of the previous editionswhile bringing all the information up to date. Many new illustrations have beenselected from a variety of sources, and several chapters have been rewritten inthe light of recent research. $6.00

Manual forComparative Anatomy

Revised EditionBy Leonard P. Sayles

This manual features a unique arrangement, listing parts in one column, eachfollowed by the descriptive material. Either type study or comparative study ofsystems is facilitated by this method. The revision includes 37 new illustrations,bringing the total to 92. All illustrations are fully and directly labelled. To bepublished in August.

Fundamentals of ComparativeEmbryology of the Vertebrates

Revised EditionBy Alfred F. Huettner

Maintaining the same general plan of organization and morphological point ofview, the revised edition of this popular text has been brought completely up todate. Two completely new chapters have been added; one on the history andtheories of development, and the other on the embryology of the mammal. Theoriginal drawings by the author are unsurpassed in biological textbooks. $5.00

THE MACMILLAN COMPANY, 60 Fifth Avenue, New York 11July 21, 1950 9

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SCIENCE, Vol. 112

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SCIENCE, Vol. 112

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SCIENCE, Vol. 112

STATHAMPhysiological Pressure Transducers

A-| ~~EKG|

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The Model P23 pressure transducers were specifi-cally designed for. the purpose of.measuring and re-cording arterial and venous blood pressures. Thesystem illustrated above demonstrates how simplymeasurements can be obatined with Stathamtransducen.

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Accuracy, reliability, simplicity, and speed are the most important considera-tions in the selection of counting room equipment. The instruments illustratedabove and listed below provide the most desirable unit for this purpose.

7. SC- 7 B Autoscaler2. SC-9C Shielded Manual Sample

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5. TGC- Geiger tube or TGC-2Geiger tube

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Special equipment which will operate with this basic unit is also availablefor completely automatic counting. For further information on the selection ofequipment for a radioactivity laboratory write for Bulletin S-25.

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