Thirty snakes were prepared for this study and most speciments were infused with 10% gelatine added indian ink or vermillion. The infused cranium was fixed with 10% formalin and decalcified and then embedded in celloidin to be cut into 300 to 500 microns transparent serial sections or into 30 microns Hematoxylin-Eosin stained sections. The so-called soft tissues was taken out from the cranium in a few specimens and observed their tooth attachment. The obtained results are as follows. 1. Bones having teeth are the maxilla, mandibula, pterygoid and palatine bones and each of these bones has a long and small calibered canal, which runs parallel to the dental arch. 2. Each tooth has a dental porta on the lingual and labial surface of the dental pedicle, depending on the kind of dental arch. 3. A cavity of the dental pedicle connects with the neighbouring one through a foramina and also connects with the long canal through the short canal or fissure. 4. The maxillary, palatine and pterygoid branch of the infraorbital artery supplies the respective bone and dental arch. 5. The mandibular artery supplies the mandibular bone and its dental arch. 6. These branches can be divided into two ; one of them enters the long canal and another runs along dental arch. These two branches become two main sources of the dental arteries and therefore they should be called the first and second types, respectively. 7. The first arterial type runs along the dental arch and sends many twigs to the dental porta to supply the dental pulp, or also supplies the tooth germ. 8. The second arterial type runs in the canal and sends some twigs into the cavity of the pedicles. These twigs make a long vascular plexus with the corresponding venous roots and then this plexus sends a few branches into the dental pulp which supply small part of the pulp. This plexus passes through the wall of pedicle to connect with neighbouring plexus. 9. From view point of the tooth development, the first arterial type supplies the tooth germ and mainly supplies the attached tooth. When the tooth attached to the basal bone, the above mentioned plexus of the second arterial type sende small twigs to the small part of dental pulp.

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Although data obtained are yet incomplete, we have got some clinical evidences pointing to the positive association existing between administration of tetracycline analogs and pigmented deciduous teeth, the summary of which was given as follows. 1. Visual observation of the teeth could discriminate a variety of pigmentation due to administration of antibiotics ranging from yellow to brown, yellow-brown and darkish yellow-brown shades. So far as the present study is concerned, it is yet undecided whether this variation of shades is due to some kind of oxidative changes with progressive time or due to combined use of multiple antibiotic agents. 2. Observation on the progress of dental caries seemed to show that the progress was retarded by administration of antibiotics. 3. As far as the present cases are concerned, the presence of fluorescent streaks is localized in the dentine of the tooth, and all these streaks also ended within the dentine. 4. Time at which the antibiotics were given and dosis of administration would seem to have possible relation with the distances between each fluorescent streaks and their degree of brightness observed. 5. It would seem that the antibiotics as used in the present study had strong affinity to tissues in the course of calcification and to the dental hard tissues in formative stage. 6. It may be particularly notable that the cases presented in this study are consisted all of children by mature birth.

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1. The authors encountered a case of dilantin gingival hyperplasia accompanied with hirsutism for a 4-year-old girl of cerebral infantile paralysis. 2. The roots of <A|A>___- had not been formed. 3. One of the chromosomes had been fissured. 4. The dilantin gingival hyperplasia in this case may be somehow attributed to the adrenal cortical insufficiency. 5. Oral findings showed remarkable hyperplasia of whole gingiva. Histological observations on the excised gingiva showed hyperplasia and slight hyperkeratinization of epithelium, deep extension of rete pegs into proper layer, hyperplasia of connective tissue and increase of collagen fibers in proper layer, and mild infiltration of round cell surrounding blood vessels. Hirsutism of the upper and lower extremities was found as general findings. 6. Observations are still being kept on the course of this case.

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Abnormalities of teeth can frequently be observed clinically. Anomalies in size, formations of abnormal cusps and anomalies of the root are recognized as the case of anomaly in shape of the teeth. Anomaly in size includes macrodont and microdont. Abnormal cusp includes incisor tubercle, canine tubercle, central cusp, Carabelli's cusp, paramolar cusp and distomolar cusp. Besides there above, formation of dentes concreti, of dentes confuse, of dentes geminati and of dens in dente are recognized as the case of rare abnormality. Nor resent experience of the complicated case of microdont, abnormal cusp and dens in dente has been reported. 1. Recently we experienced a rare case of 23 years female who has microdont abnormal cusp and dens in dente. 2. Microdont was apparent on [numerical formula]. 3. Abnormal cusp was apparent on <31|123>___-. 4. Dens in dente was apparent on |2__-and |5^^-. 5. The enamel substance of the outer tooth dens in dente |5^^- was histologicalsound like that of ordinary tooth. The dentin of the outer tooth also showed normal appearance in structure with its dentinal tubules well mineralizde. The pulp tissue was almost necrosis. The cementum of the outer tooth was normally deposited.

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