This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1921 Excerpt: ... Larger secondary spermatocytes, anaphase. Fig. 16. Larger secondary spermatocyte, telophase. Figs. 17, 18 And 19. Larger spermatids. PLATfc II. Plate III. Figs. 20, 21, 22, 23 And 24. Smaller secondary spermatocytes, metaphase. Figs. 25 And 26. Smaller secondary spermatocytes, anaphase. Fig. 27. Smaller secondary spermatocyte, telophase. Figs. 28, 29, 30 And 31. Smaller spermatids. Plate IV. Figs. 32 And 33. Smaller spermatids. Figs. 34, 35 And 36. Retrogressing smaller spermatids. Fig. 37. Retrogressed cell of the smaller spermatid. Fig. 38. Layers of the retrogressed cells. OF THK flDarine Biological Xaborator? WOODS HOLE, MASS. Vol. XLI July, 1921 No. 1 CONTENTS TAGE Twenty-third Annual Report, Marine Biological Laboratory i Whiting, P. W. Studies on the Parasitic Wasp, Hadrobracon brevicornis ( Wesmael), I. 42 Shull, A. Franklin Cht omosomes and the Life Cycle of Hydatina sen/a 55 Published Monthly By The MARINE BIOLOGICAL LABORATORY PRINTED AND ISSUED BY THE NEW ERA PRINTING COMPANY, Inc. LANCASTER, PA. Agent For Great Britain WILLIAM WESLEY & SON iS Essex Street, Strand, London, W. C. Single Numbers, 75 Cents. Per Volume (6 numbers), S3.00 Entered October 10,1902, at Lancaster. Pa., at MCond-elaii matter nadir Ast at Cong-reti of JuIy 16, 1894. EMtorial Staff E. G. Conklin--Princeton University. George T. Moore--The Missouri Botanic Garden. T. H. Morgan--Columbia University. W. M. Wheeler--Harvard University. E. B. Wilson--Columbia University. /Managing Editor Frank R. Lillie--The University oj Chicago. All communications and manuscripts should be sent to the Managing Editor) the University of Chicago, Sept. 15th to June 15th, or Woods Hole, Mass., June 15th to Sept. 15th. Subscriptions and other matter should be addressed to the Biological Bulle...