魚類歯牙の形態学的研究

I.鯛の歯牙に就いて

抄録

1. Materials and Methods.
Materials are the teeth of upper and lower jaws of five kinds of the porgies which are common in Japanese waters. They are Pagrosomus major (TEMMINCK et SCHLEGEL), Evynnis japonicus TANAKA, Sparus swinhonis GÜNTHER, Taius tumifrons TEMMINCK et SCHLEGEL) and Argyrops cardinalis (LAÉPÈDE. All of them are 20-60 Cm in length.
Methods used were: microscopic observation of the bleached-bone, and microscopic observation of ground, paraffin and celloidin sections.
2. Findings.
The teeth consist of crown and root areas; they are joined by a contact area; and they are together surrounding the pulp tissue. The root area spreads to jaw-bones.
a) The teeth are divided into outside and inside teeth by their arrangement. Two or several of the anterior-outside teeth are especially large and spear-form; inside and posterior-outside teeth are of various size and bowl-or, grain-form. However, only Taius tumifrons does not show the bowl-form. Color is yellowish-white or light yellow, but Sparus swinhonis shows a tinge of black.
b) The crown area consists of enamel and dentin (inside dentin, outside dentin); and the root area consists of dentin.
The enamel is the so-called “tubular enamel” in which the tubules of fibrous structure cross each other in middle layer of enamel, and it may be seen as a brown zone.
The outside dentin is placed between enamel and inside dentin, seems to be a primary cement; and dentinal tubules have branches and end in the middle layer of the outside dentine.
The inside dentin has dentinal tubules similar to human dentin, and these tubules are running with S-shaped curves. In this layer are found the dentinal lamellae, Owen's contour lines and praedentin, but the writer has never seen interglobular dentin and Tomas' granular layer.
In the dentin of root area is found a osteoid-dentin that has dentinal tubules near the crown area and osteodentin which has no dentinal tubules and is under the osteo id-dent in.
c) The pulp tissue chiefly cons: sts of fibroblasts and fibrocytes. There are odontoblast layer in the surface of pulp tissue, and the pulp tends to be fibrous. The dentinal fibers are long, slender protoplasmic processes projecting from the cell into a dentinal tubule and running through the tubule to the outer surface of the dentin.
d) The contact area is fibrous, not calcified, and seems to be a retentive apparatus of the crown area.
e) Moreover, there is a fibrous layer which seems to be a “Grenzfasershicht” as stated by M. MORGENSTERN.