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Openings of the central canal in the filum terminale internum of the rabbit, guinea pig, and rat have been studied by light and electron microscopy. There were two openings in the rabbit, two or three in the guinea pig, and one in the rat. They opened dorsally and were of two types; one type was without a pial covering, the other with a pial covering. In both types, a focal junctional apparatus associated with increased density of the subjacent cytoplasm was observed between the pial cell and the ependymal cell at the margins of the opening, where the basal lamina on the surface of the filum terminale showed a characteristic ending for each species. Injections of india ink into the lateral ventricle of the brain indicated that the cerebrospinal fluid of the ventricular system drains out of the central canal by way of these openings, into the subarachnoid space. Reissner's fibre of the rabbit and rat consisted of a mass of moderately electron dense fibrous material containing many small vesicles in the central canal of the filum terminale. This mass passed through the openings into the subarachnoid space and continued into the subdual space.

A 49‐year‐old woman was admitted to the hospital with a palpable mass in the right hypochondrium. A laparotomy was performed under the clinical diagnosis of a solitary cyst of the liver. The cystic lesion of the liver was removed. Although the histological finding of the cyst wall showed a similarity to hepatocellular carcinoma of trabecular pattern, the tumor cells with uniform nuclei and little mitotic figure were positive for both argyrophil and argentaffin reaction. The pathological diagnosis was metastatic carcinoid tumor of the liver. There was no carcinoid syndrome nor the other clinical symptoms after the operation and various postoperative examinations could not reveal a primary site of the carcinoid tumor. The cystic lesion of the liver recurred ten months after the first operation and a second laparotomy was performed to reveal the primary site in the ileum: three submucosal tumors, 0.8, 0.7, and 0.3 cm. in diameter, two of them, however, extended into the muscle wall or subserosa and conclusively, the small lesion of the ileum metastasized into the liver as a large pseudocystic lesion.

Ova are captured by the oviductal fimbria and rapidly transported to the ampullary-isthmic junction of the fallopian tube. Fertilized ova and oviductal fluids are then carried medially in the fallopian tube, while undergoing maturation in preparation for entering the uterine cavity, where nidation and further development take place. This movement of oviductal fluids was visualized in a rabbit model with human chorionic gonadotropin-induced ovulation, by injection of a contrast medium into the ampulla region of the oviduct. In the ampulla, the opaque medium was observed to oscillate at 0-85.4 mm/s. This medial transport of the fluid towards the uterus decreased to 0-9.6 mm/s in the isthmic portion of the tube. This decrease substantiates previous findings that the transport of material in the isthmic portion of the oviduct is more strongly under the control of ciliary action than under peristaltic activity.