The three cell types known to form the hepatic sinusoidal wall were electron microscopically observed in three kinds of bats captured in winter and summer.
1. The cytoplasmic extensions of sinusoidal endothelial cells consisted of continuous thicker parts (“cytoplasmic processes”) and discontinuous thinner parts (“sieve plates”). The alternate disposition of the two parts was rather irregular, and the sizes, shapes and spacings of the fenestrae were variable. In the thinner parts with numerous small fenestrae, larger gaps were also mingled. The endothelium was simple-layered and devoid of basal lamina. Interendothelial junctions were found mainly between closely apposed margins of the “cytoplasmic processes” and agreed in structure with the “junctional complex” of WISSE (1970).
2. Kupffer cells, morphologically distinct from the endothelial cells, bulged strongly into the sinusoidal lumen. Provided with many microvillous pseudopods, they were stellate in appearance. They were fixed to the endothelial lining by small junctional areas which occurred between the Kupffer cell body and the “cytoplasmic processes” of the endothelium.
3. Fat-storing cells were located in the Disse's space. They generally contained only smaller amounts of lipid in a few droplets. So-called empty fat-storing cells were numerous, especially in winter bats. The perikaryonal cytoplasm revealed a large Golgi complex and well-developed granular endoplasmic reticulum. The three mesenchymal cell types of the sinusoidal wall possessed the centriole in common within the Golgi complex, but only the fat-storing cell was provided with the single cilium. Fat-storing cells extended cytoplasmic processes ramifying beneath the endothelial lining occasionally surrounding the sinusoids almost completely, and which seemed to reinforce the endothelial lining and to bring about the constriction of the sinusoid. In hypervitaminotic bats that daily received 6, 000 I.U. vitamin A for three days, remarkable increase in size and number of lipid droplets was observed in slightly hypertrophic fat-storing cells, and the empty cells disappeared simulating an increased number of fat-storing cells. Suggestion was made of an antidotal function of fat-storing cells against excess vitamin A which might be considered a toxic agent in the broad sense.
4. The Disse's space of bat liver contained plasma cells, lymphocytes and macrophages, the latter two often being under migration through the endothelial fenestrae.

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The endocrine cells of the pyloric region of the Japanese quail have been studied by light and electron microscopy.
The quail pyloric region is a narrow circular zone (about 2mm in width) between the gizzard and the duodenum. The endocrine cells are concentrated in this region, and they are represented by argyrophil cells.
At least five types of endocrine cells are identified in this region by electron microscopy. Type I cells are characterized by having round and large granules (350-550nm in diameter) whose contents are high to moderate in electron density. Type II cells are characterized by their round and medium-sized granules (250-350nm) which possess a dense core and a clear halo. Type III cells are characterized by the presence of round and small-cored granules (150-250nm). Type IV cells contain round and large granules (350-550nm) of high to low electron density. Type V cells are identified by the occurrence of microfilaments and polymorphous granules of high electron density. All five cell types are recognized as open type cells.
The type I, II and III cells are located mainly in the lower half portion of pyloric glands, and the other cell types are located only in the upper half portion of the glands. The type I and II cells are found much more frequently than other cell types. The relationships between the endocrine cells in the quail pyloric region and those of the mammalian digestive tracts were discussed.

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Endocrine glands of the ironfish were studied light microscopically to elucidate the relationship between the races of the genus Carassius. The rostral pars distalis of the adenohypophysis consists mainly of acidophils corresponding to prolactin cells and lead-hematoxylin positive cells corresponding to corticotrophs (ACTH cells). The prolactin cells are obviously arranged in the form of follicles. The proximal pars distalis contains orangenophils (STH cells) and two types of basophils (TSH and GTH cells). In the pars intermedia, three types of cells are identified: periodic acid Schiff positive cells, lead-hematoxylin stainable cells and orangenophils containing PAS positive coarse granules. In addition, small agranular cells are seldom demonstrated in the entire adenohypophysis. A considerable amount of aldehyde fuchsin positive neurosecretory material is laden in the cells of the nucleus preopticus and in the pars nervosa. The nucleus lateralis tuberis is composed of three portions: pars anterior, pars posterior and pars lateralis.
The thyroid follicles found in the pharyngeal region and head kidney show a mild state of activity. The interrenal cells intermingled with the chromaffin cells have a considerable amount of eosinophil cytoplasm. Judging from the gonadal condition, the breeding season of the ironfish may extend to the end of July.

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Visceral and costal pleurae of the rabbit were studied by light and electron microscopy in the normal state, after India ink injection into the pleural cavity and in pleuritis induced by intrapleurally injected adjuvant.
In normal rabbits, the mesothelial cells in the visceral pleura had more numerous microvilli and pinocytotic vesicles than in the costal pleura. The surface coat on the microvilli was much thicker in the former than in the latter.
Intrapleurally injected India ink particles were phagocytosed by mesothelial cells and macrophages. This phagocytotic activity was more prominent on the costal side than on the visceral side.
In rabbits with adjuvant induced pleuritis, the visceral pleura, but not the costal pleura, showed mushroom-like projections on the pleural surface which were composed of a fibrin mass mixed with phagocytotic macrophages and covered by proliferative mesothelial cells. These hitherto poorly known structures, which were formed, though less conspicuously, also after India ink administration, seemed to play an important role in the initial protection of the lung against foreign body invasions from the pleural cavity. With the progress of pleuritis, the mushroom-like projections changed into patchy granulation tissues which were well localized and did not exceed the elastic layer. In the costal pleura, apparently due to a poorer protective mechanism than in the visceral pleura, granulation tissue was formed much more extensively and diffusely.
No signs of transformation of mesothelial cells into fibroblasts were recognized.
Fat-containing cells closely resembling the Ito cells in the liver occurred in the submesothelial and subpleural layers of the visceral pleura.

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The taste bud of the vallate papillae of the rat has been examined in the electron microscope by using the freeze-fracture technique.
Tight junctions as a junctional complex are located at the taste pore, and form a seal between the oral environment and the taste buds. Tight junctions are not only within the taste buds, but also are demonstrated in the granular cell layers of the surrounding lingual epithelium. The present finding suggests that tight junctions of the taste pore link with those of the lingual epithelium. Desmosomes are observed in the buds, but they are smaller in size than in the surrounding lingual epithelium. Besides these junctions, within the buds, gap junctions containing particle-free zones are demonstrated which are called a subcompartment type.

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