Immature, mature unfertilized and fertilized eggs of Japanese seaurchin,Helocidaris crassispina were observed both with the light- and electron microscope, in order to examine various states of ribonucleic acid containing structures.
1. A great number of minute granules and microvesicles which were comparable to the microsomes reported by Claude ('43) were found to be actually scattered freely in the cytoplasm of sea-urchin eggs.
2. So-called yolk-nuclei of sea-urchin eggs are composed of canaliculi or double membrane structures, whose morphology is reminiscent of the endoplasmic reticulum. Features to be considered as transitional forms between this component and microsomes were noted.
3. The aster and spindle of the mitosis were seen in tubular shape in their full-formed states and as granular chains at the beginning of their development and at their reducing stage.
4. The nuclear envelope, which is directly continuous with the cytoplasmic double membranes or canaliculi at the resting stage of the cell, may be formed by the reorganization of microsomes at late telophase.
5. After the light microscopic examination with various basic dyes, free scattered microsomes, asters and spindle as well as the cytoplas- mic double membranes or canaliculi were recognized to contain appreciable amount of RNA.
6. It is conceivable from the above facts that the microsomes can serve as the common origin of cytoplasmic double membranes or canaliculi, nuclear envelope, and the achromatic figure in mitosis. Thus these structures were tentatively combined to a single cytoplasmic system, here called“microsome system”. The components of this system may be transformed from one into another associating with the physiological condition of the cell.

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1) I devised a new method which demonstrates as a curve the proportion of volume of whole cell-bodies to that of all gray matter in the cerebral cortex.
2) Though the curve has no direct relation to forms and sizes of cell-body, the quantity of cell-volume at the voluntary zones horizontal to the cortical surface can be easily got at a glance.
3) Using this method, areas 4 and 17, where it may be visible the most specific cytoarchitectonic structure, were chosen to be examined. Following results were obtained:
i) At area 4, the volume-quantities at the superficial zones of the cerebral cortex were rather high and decreasing with depth, except a zone which corresponds with a place of Betz's cell, where a sharp peak was shown. The general transition of the curve did not correspond with the stratification which had been defined by cytoarchitectonic investigators.
ii) Contrary to area 4, at area 17, there was some correlation between the curve and the stratification. For instance, a curve has five peaks, which correspond with II, IVa, IVb, IVc, and Va by Brodmann. And the highest quantity was seen at II layer, the lowest at IVc, and at the other laminae they took intermediate values between them. These relations were almost the same for five cases.
The curves obtained at summit, side, and valley of a gyrus differed with each other.
4) Some technical problems and the possibility for measurements of the whole volume of cell-bodies in the cerebral cortex were discussed.

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The authors reported a case of the presence of ganglion cells in the parenchyma of the thyroid gland of a horse.

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This paper presents the observations of the thyroid follicular pattern of nowborn babies ranging in age from shortly after birth to two months old. Investigation was conducted in three ways: first by observing histologically transverse sections of thyroid lobes, second by preparing folliculograms (Sugiya ma and Ohida, '54), and third by the preparation of wax plate reconstruction models, and it elucidated the following: Thyroid glands are not solid in type and are composed of colloidcontaining follicles exclusively. The lobulation is not distinct, but only in the peripheral zone of the gland. Follicles are not completely dissociated. Follicles of moderate to small sizes connect often with each other and form follicular networks and chains. The follicle connection may be suggested to be a proliferative sign, present and past, of follicles through the budding process. Large follicles appear surrounded by a zone of small follicles and may resemble in arrangement the so-called“Zentralkanälchen”or“Sammelgänge.”But no communication of cavities is found between them. Some of the large follicles are irregularshaped and have several, sometimes many pockets leading off from the main cavity, and this reminds us of the description (Sammelgänge) of Hammer and Loeschcke ('34).

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