249. Later tetrad stage.
250-251. First spermatocytes, metaphase from mercuro-nitric material.
252-254. Similar stages from Hermann material, showing longitudinal split in both the bivalents, and the odd chromosome (x).
255. First spermatocyte, anaphase.
256. First spermatocyte, telophase.
257. First spermatocyte, daughter plates containing 11 and 12 chromosomes, respectively.
258. First spermatocyte, a and c daughter plates, each containing 11 chromosomes, x the odd chromosome at a different level (b).
259. Second spermatocyte, equatorial plates of the two classes.
260. Second spermatocyte, metaphase.
261. Second spermatocyte, anaphase.