166 
Spermatogenesis in Ixodes 
Montgomery (1905). Spermatogenesis of Sysbula and Lycosa. Proceed. Acad. Nat. Sc, Phil . 
Oettinger (1909). Zur Kenntniss der Spermatogenese der Myriopoden. Archiv f . Zell - 
forschung, m. 
Tonniges (1904). Beitrage zur Spermatogenese, etc. bei den Myriopoden. Zeitschr. f . wiss . 
Zool. LXXI. 
EXPLANATION OF PLATE XI. 
The figures have been drawn with an apochromatic Zeiss lens 2 mm., and a compensation ocular 
No. 8 (tube-length 160 mm.), giving a magnification of 1000 diameters; they were projected 
on the working table through a camera of Abbe’s model. Figs. 1-5, 20, 23 and 27 were drawn 
from preparations fixed in Carnoy, the others from Flemming preparations. Heidenhain’s 
iron-alum haematoxylin was used as a stain throughout. 
Fig. 1. Spermatogonium in resting-phase. 
Fig. 2. Resting spermatocyte of first order. 
Fig. 3. Telophase of second maturation division, with centrosome and remnant of spindle. 
THE SPERMATID. 
Fig. 4. Resting phase. 
Fig. 5. Showing contraction of nucleus. 
Fig. 6. The same, with remnant of spindle visible. 
Fig. 7. Elongating nucleus, centrosome, and thickening of ectoplasm. 
Fig. 8. The nucleus has assumed a rod-shaped form, vesicles are appearing in the ectoplasm and 
the endoplasm shows aggregations of mitochondria, and conical protrusion. 
Fig. 9. Nucleus seen in transverse section. 
Figs. 10-11. Successive developments of nucleus ; centrosome visible. 
Fig. 12. The same, showing endoplasm growing round ectoplasm, and appearance of metachon- 
drial bodies. 
Figs. 13-15. Showing convolution of the nucleus, enlargement of the ectoplasm-vesicles, and 
further development of the mitochondrial body. 
Fig. 16. Showing growth of endoplasm round ectoplasm. 
Fig. 17. The,same, the centrosome at extremity of nucleus. 
Figs. 18-19. Showing expansion of the ectoplasm-vesicle, and the protuberant mass of endo¬ 
plasm containing the coiled nucleus and mitochondrial body. 
DEVELOPMENT OF THE SPERMATOZOON. 
Fig. 20 a, b, c. Phase of plasma expulsion and formation of tail-shaped appendix. 
Figs. 21-22. Showing the plasma appendix separating from the cell body, elongation of ecto¬ 
plasm-vesicle, and nuclear changes. 
Fig. 23. The plasma appendix begins to disappear. 
Fig. 24. The endoplasm forms a thin covering to the ectoplasm, with mitochondria between the 
two. 
Fig. 25 a, b. Successive movements of the nucleus; the mitochondrial body has assumed a 
conical shape. 
Fig. 26. Showing extension of nucleus along the plasma-rod; the central stainable cord of the 
latter is now visible. 
Fig. 27. Showing transverse section of mitochondrial body in same phase as Fig. 22; part of the 
nucleus also appears in the section. 
Figs. 28-29. Spermatozoa in transverse section, showing folding of central cord. 
Figs. 30-31. Speimatozoa; final stage of development. Fig. 30 shows a spermatozoon from the 
vas deferens; Fig. 31 a somewhat younger stage with centrosomal corpuscle. 
