271. Resting nucleus of a young oöcyte before synapsis, showing two pairs of condensed chromosomes, corresponding in size to the m-chromosomes and the odd chromosome of the spermatocytes.
272-277. Sections of nuclei of oöcytes, showing one or more of these heterochromosomes, from safranin-gentian preparations.
278-279. Bouquet stage from iron-hæmatoxylin preparations, showing the heterochromosome bivalent (x).
Cacœcia cerasivorana (Lepidoptera).
280. First spermatocyte, synizesis stage, showing 2 condensed chromosomes (x1 and x2).
281-282. First spermatocyte, synapsis stage.
283-284. First spermatocyte, growth stages.
285. First spermatocyte, prophase.
286-287. First spermatocyte, later prophases, showing the heterochromosome pair (x).
288. First spermatocyte, metaphase.