31. Wagner, J., 1896. Beiträge zur Kenntniss der Spermatogenese bei den Spinnen, Arb. Nat. Ges. St. Petersburg, vol. 26.
32. Wilcox, E. V., 1895. Spermatogenesis of Caloptenus femur-rubrum and Cicada tibicen, Bull. Mus. Comp. Zool. Harvard Univ., vol. 27.
33. Wilcox, E. V., 1896. Further Studies on the Spermatogenesis of Caloptenus femur-rubrum, ibid., vol. 29.
34. Wilcox, E. V., 1897. Chromatic Tetrads, Anat. Anz., vol. 14.
35. Wilcox, E. V., 1901. Longitudinal and Transverse Divisions of Chromosomes, Anat. Anz., Bd. 19, No. 13.
36. Wilson, E. B., 1900. The Cell in Development and Inheritance. New York; 2d ed.
37. de Sinéty, R., 1901. Recherches sur la Biologie et l’Anatomie des Phasmes, La Cellule, Tome 19, 1er fascicule.
DESCRIPTION OF FIGURES.
Drawings were made with a camera lucida, the optical combination being a 1–16 B. & L. objective and a Watson “Holoscopic” ocular No. 7. Details were studied with a Zeiss 2-mm. apochromat, N. A. 1.30. As reduced in reproduction, an enlargement of 1500 diameters exists. Photomicrographs, excepting those of figures 37 and 38, were made by the use of the arc light and horizontal camera. The exceptions represent illumination by ordinary diffuse daylight. In all cases the lenses used were the Zeiss 2 mm., N. A. 1.30 objective and projection oculars. A Watson “Parachromatic” oil-immersion condenser of 1.30 N. A. was employed to illuminate the objects. In use it was stopped down to between .75 N. A. and 1.0 N. A.
Explanation of Plate VII.