The hard tissue of three parts of enameloid, dentine and teeth attachment of jawteeth of Stone flounder (Kareius bicoloratus) were observed with an optical microscope and scanning electron microscope.
The results were as follows:
1) Enameloid. The jaw teeth of Stone flounder were covered with the cap enameloid at the tip of the teeth and the collar enameloid toward base of the teeth. The cap enameloid was a tubular enameloid. By looking through the scanning electron microscope, it was recognized by the a small hole (0.6-2μ diameter) and the fibrous-like structure projected from a small hole on the enameloid surfase. Furthermore both of the enameloid junction existed in the development groove of fiss ura.
2) Dentine. The dentine consisted of orthodentine and homogeneous dentine, and was located within about 25μ below the dentino-enameloid junction in the dentine layer which was made of three different species from fibrous bundles. One was coarse mantle fibrous bundles made with fine fibrils, the second coarse fibrous bundles (10-15μ diam.) in the interior of the dentine proceeded toward the mantle firbous bundles, and the other dense irregular fibrous (about 20μ diam.) were found to made by dentine with root extremity in dentine. The dentinal tubules were radially arranged from interior to exterior in dentinal layer, and they were not observed at the peritubular dentine and dentinal fiber. However the dentinal tubules appeared in the histologi cal interrelation of the blood capillaries, and these results suggested that the dentinal tubule was considered a tub ule of the dentinal fluid.
3) teeth attachment. The combination of the jaw teeth and bone of attachment a ppeared in the formation reticularis arranged with the collagen fibrils. Furthermore the side teeth connection was strongly bound through the intermediary of the connective tissue as intermediate plexus, and the change-over of the osteoid was found in the tissue.

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Serological studies were carried out with isolated and reference strains. Extract was prepared according to the method of Rantz and Randall, and antiserum was prepared by immunizing rabbit with formalin-killed organisms.
Precipitin reaction (ring prove) was observated for 2 hours at room temperature.
The antigen titer of the strain belonging to S. sanguis type I is almost constant, 1: 128-1: 256, while the antibody titer is not constant. In the serological experiment, antiserum with as high antibody titer as possible was used.
Among the extracts in twofold dilution made of streptococci isolated from the dental plaque, precipitin reaction were carried out only in 39 strains reacting intensely with S. sanguis type I antiserum alone, and 35 strains of these were identified as S. sanguis type I. The biological properties of these strains resemble those of S. sanguis type I.
Strains Challis and M-5 were found to be serologically most similar to S. sanguis type I-II ATCC 10558. Strain 8144, 12396, F 90 A and Wicky in the group H streptococcus gave different results.

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The vomeropalatine teeth of a pycnodont fish from the middle Eocene of Republic Mali, Africa, were investigated by the methods of gross observation of tooth morphology and arrangement, X-ray diffraction of powdered sample, optical and polarizing microscopic observation and microradiography of ground section, and scanning electron microscopic observation of ground section.
The length of the vomeropalatine bone was 87.5 mm+. On the ventral surface of the vornneropalatine, the teeth which had circular or elliptical occlusional surface were arranging like as Indian corn. Although the arrangement of the teeth was irregular, 11 tooth rows could be observed.The median tooth row was composed of the largest teeth. This arrangement pattern was similar to other pycnodonts fundamentally, but the numeruos tooth rows were markable peculiarity of this pycnodont fish.
The mineral component of the tooth was mainly apatite. The tooth was consisted of the outer-layer (enamel) and the inner-layer (dentin), and the latter was projecting downward into the basal osseous tissues at the marginal portion of the tooth. The original wide dental pulp cavity was filled with the osseous tissue. The outer-layer was the main hard tissue of the tooth (the thickness was about 2 mm), and indicated a very high degree of radiopacity. The tubules which continued from the dentinal tubules in the inner-layer were penetrati ng the outer-layer of the tooth. The lower part of the outer-layer was consisted of the bundles of the crystallites which were crossing each other, while the upper part of the outer-layer was consisted of the crystallites which were arranged in parallel at the right angle to the tooth surface. By the decalcification of the ground section of the tooth, the mineral component of the outer-layer were melted enti rely, but the tubules in the outer-layer were remained and stained by hematoxylin. The inner-layer of the tooth was very thin layer (the thickness was about 0.4 mm) beneath the outer-layer and indicated a lower degree of radiopacity. In the decalcified ground section, the inner-layer of the tooth was stained by hematoxylin and contain the incremental lines whose intervals were about 13μm. The inner-layer of the tooth was consisted of both the bundles of the dentinal tubules which arose from the small -pulp cavities beneath the inner-layer and the intercalated portion which had very few dentinal tubules. The latter was surrounding the former and was composed of a fibrous osseous tissue which continued to the periodontal osseous tissues. The junction between the outer-layer and inner-layer of the tooth was very obviously by the difference of crystallites size, hematoxylin stainning and radiopacity, while the inner-layer of the tooth was continuous to the periodontal osseous tissues. Therefore, the tooth was firmly anchylosed to the surrounding osseous tissues of the vomeropalatine.
From the arrangement, structure and attachment of the tooth, it is considered that this pycnodont was one of the most specialized fish for shell-bearing mollusc diet in pycnodontiformes.

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