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The development of ventricles in the brain of H. huso (Beluga sturgeon) from 1 to 54 days old is presented in this study. The components observed in the 1-day-old ventricular system were the telencephalic, tectal, and cerebellar ventricles. These ventricles were not observed to have any recess or sulcus. They were surrounded by copious ependymal and embryonic cells. Two different parts were detected in the 6-day-old telencephalic ventricle: the olfactory and lateral ventricle. The olfactory ventricle was observed as a cranial extension of the telencephalic ventricle from 6 days old, as was the inner cell layer of the olfactory bulb (ic) adjacent to this extension. In the preoptic region, the lateral ventricle was connected to the preoptic recess from 15 days old, and this recess was connected by the interventricular foramen to the third ventricle in the diencephalon. At 6 days old, the third ventricle in the diencephalon was visible at the caudal part of the lateral ventricle, and the third ventricle had a recess near to the inferior lobe of the hypothalamus. At 6 days old, the tectal ventricle was observed to have bilateral extensions which proceeded to grow with age. The cerebellar ventricle, situated between the two lobes of the cerebellum, was observed from 1 day old. The cerebellar ventricle grew with age, extending laterally from 6 days old. The connection of the cerebellar ventricle to the fourth ventricle in the medulla oblongata was visible from 6 days old. Upon dividing the ventricular system into three regions (forebrain, midbrain, and hindbrain), stereological studies performed utiizing Cavalieri's principle indicated that the forebrain ventricular region had the smallest volume while the hindbrain ventricular region had the largest.

In basic sciences, laboratory animals have a special role in investigations. In this study, the adrenal of three adult female guinea pigs and hamsters were studied. The left adrenal was larger than the right in two species. In hamster, it was in the cranial pole, and in guinea pig, it was in the craniomedial pole of the kidney. In guinea pig, the right and left glands were bean shape and in hamster, egg shape. This gland was covered by a capsule without muscle fibers in guinea pig and hamster. The peripheral cortex in hamster was divided into three zones and in guinea pig, four zones. Zona glomerulosa was composed of arcuate cords in guinea pig and clusters in hamster. The foamy cytoplasm of fasciculate in guinea pig was more than hamster. There was also a lot of lipofuscin in cytoplasm of reticularis in the two animals, especially in guinea pig. The medulla in guinea pig was long and in hamster was egg-shaped. In guinea pig, reticularis cells penetrated into medulla and invagination of cortex also was obvious in medulla of this species. In chromaffin reaction, the less electron-dense granules were epinephrine and the dense granules were norepinephrine cells.

Fish skin is essential for survival, maintenance of body shape, and protection against the shock and infection. During week 1 of sturgeon larval development, the epidermis is thin and not differentiated in various layers yet, but by week 4-6 the thickness increases and various layers appear, depending upon the region of the body. Mucous cells differentiate early in development on the surface of epithelium and contain acid and neutral mucopolysaccharides. Primordial sensory buds are visible within the epithelia of the skin of the head in week 1 larvae, and become numerous during later larval development. Club cells are specialized epidermal cells that have an immune function and appear in the middle layer of the head and trunk epidermis on week 4.

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