Philadelpia: The American Philosophical Society, 1940. Hard Cover.

Ink stamps on edges and front endpapers, bookplate on front endpaper, ink names on front endpaper and title page.

xv, 219 pp. Includes 85 figures and 4 tables. Includes: Preface and Acknowledgments; Introduction; Reproductive System and Germ Cells of Urechis; Material and.....