88 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
DESCRIPTION OF FIGURES. 
Unless otherwise stated the figures are made from the cells of the testis of the guinea pig, and have 
been drawn under a 2mm. 1.40 n.a. Zeiss Apochrom. 10-inch tube, 180c. 
PLATE I. 
Fig. 1. — Resting pre-maiotic cell. 
2. — Early spirem. 
3. — Late spirem, the thread has broken up into the pre-maiotic chromosomes. 
4. — Fre-maiotic spindle figure. 
5. — Diaster. 
6. — Later stage of same. 
7. — Later stage ot same. 
8. — Reconstruction, daughter nucleus returning to rest. 
9. — Resting pre-maiotic cell, similar to Fig. 1. 
PLATE II. 
Fig. 10. — Early prophase of the first maiotic divisions. The nucleus shows chiomatin centres. 
11. — synaptic contraction. 
13. — Another view. 
14. — Eater stage in the synapsis. 
15. — Stage at which the first splitting of the thread is visible. 
16. — The contraction opening out to form the coarse spirem figuie. 
18. — Eater stage, the loops contracting up to form the gemini. 
PLATE III. 
ig. — A similar stage to 18. 
jo.— A similar stage. 
21. — Later prophase showing the peculiar appearance ot the young gemini. 
22. — Early spindle figure of the first maiotic division. 
24. — ihe same stage in a mouse. 
25. — Diaster. 
20. — Reconstruction nuclei in daughter cells. 
PLATE IV. 
tig. 27.— Resting cell before the prophase of the second 
28. — Fropnase ot the second maiotic division. 
29. — spindle figure ot same. 
31. — Daughter cells of the first maiotic division. 
32. — Resting spermatid. 
Ihree spermatic nuclei 111 a single cytoplasm. 
.4 — Inree spermatic nuclei in a single cytoplasm. 
PLATE V. 
Fig. 35. — Resting speimatids, with remains of spindle between them, and first indications of the ai 1 hfi- 
plasmic vesicles in the archoplasms. 
Figs. 36, 37, 38, 39, 40, 41, 42. — Stages showing development of the archoplasmic vesicle. 
PLATE VI. 
Figs. 43, 44, 45, 46, 47, 48, 49, 50, 51. — Stages in the development of the archoplasmic vesicle. 
PLATE VU. 
Figs. 52, 53, 54. — Stages in the development of the archoplasmic ve 
Figs. 55, 56, 57, 58. — Diagrams of spermatogenesis (see text, p. 7). 
