1. The anatomy of the female reproductive system in Chirocephalus diaphanus is described with especial reference to the paired anterior and posterior masses of uterine glands.
2. The gland-cells are arranged in pairs surrounded by a common membrane and served by a single duct formed by a separate duct-cell, representing possibly an ingrowth of the uterine epithelium.
3. The glands increase greatly in size during development owing to the formation of a granular secretion which is apparently formed in the nucleus and gradually displaces the original cytoplasm.
4. The egg-case consists of an inner membrane which is chitinous and is formed by the oviducal epithelium, and an outer thicker, rugose membrane which is non-chitinous and is secreted by the uterine glands.
5. Attention is drawn to the close resemblance to conditions in the Decapoda. The inner membrane in both cases is chitinous and formed in the oviduct, while the uterine secretion has much in common with the secretion of the cement glands, but is concerned with protection only and not also with attachment to the body of the female.