The general discussions based on the observation of preceeding papers are presented in this report.

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Assessment criterion of the brachymesophalangia 5 (hereafter abbreviated Bmp 5) was studied using radiographs of both hands of 141 male and 128 female adult Japanese.
Lengths of 2nd to 5th middle phalanges (MP2L-5L), distal and proximal phalanges (DP5L, PP5L), and breadths of 4th and 5th middle phalanges (MP4B and 5B) were measured (Fig. 2). Groups of apparently normal and Bmp 5 were selected and their means and mean differences of phalangeal measurements were calculated (Tab. 2). Apparent Bmp 5 sample had 5th middle phalanges shorter and broader than those of the normal sample, differences being significant at 0.01 level.
Coefficients of correlation between 5th and 4th middle phalanges were the largest and those between 5th middle and distal phalanges were the smallest of all coefficients between the lengths of the 5th middle phalanx and other phalanges in both sexes (Tab. 3 and 4).
Discriminant functions based on 6 measurements (MP2L-5L, MP 4B and 5B) for the above two groups were calculated for each sex (Tab. 6). Incidences of the Bmp 5 assigned by these discriminant functions were 3.2% in male and 13.7% in female (Fig. 3).
In order to find simpler criterions for the Bmp 5, various indices were examined for their frequency distributions between these assigned normal and Bmp 5 groups (Fig. 4) and for their mutual correlations (Tab. 8 and 9). As a result, the best index-criterions of Bmp 5 were found to be MP5L/MP4L<0.55 and MP5B/MP5L>0.60 in male, but in female, though the assignment by discriminant function seemed to be possible, no simple index was found effective probably because of higher occurrence of transitional forms between normal and Bmp 5 hands than in the male.

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We have reported on the pattern of the enamel-dentin border of the incisors, canines, premolars and maxillary molars in this journal (vol. 73, no. 3, vol. 75, no. 4, 5, vol. 77, no. 3, vol. 79, no. 4). The present article is the description on the mandibular molars as the sixth chapter of our work. The materials used in this study were 114 mandibular first molars and 77 second molars.
The results were summarized as follows:
1. On the enamel-dentin border, the mesial, distal and cervical margins of buccal surface may be surrounded by the distinct ridges separated from the surface itself by clear grooves (Fig. 1.). The mesial marginal ridge starts as a continuation of the cervical ridge, rises in an occlusal direction and terminates on the mesial occlusal marginal ridge. The distal marginal ridge starts as a continuation of the cervical ridge, runs along the buccal slope of the hypoconid in a disto-occlusal direction and terminates on the tip of the hypoconulid. The frequencies of the buccal marginal ridge are shown in table 1. The enamel-dentin border has a higher frquency of well developed marginal ridge than the enamel surface. The frequencies of the buccal cervical ridge on enamel-dentin border are shown in table 2. The first molar has markedly higher frequencies of the marginal and cervical ridges than the second molar. Buccal ridges may be homologous with the buccal cingulum and its ascending portion observed in the mandibular molar of Teilhardina or recent gorilla.
2. In almost all cases the enamel-dentin borders of the teeth with protostylid show the well developed buccal cingulum (Fig. 4). In many cases this cingulum shows a cingulum-protoconid crest. The enamel-dentin borders of the teeth without protostylid on the enamel surface show a more or less distinct cingulum on nearly 28-56 per cent of the cases. The degree of development of the protostylid on enamel surface and that of the buccal cingulum are significantly correlated with each other under 1 per cent level. The evidence adduced above suggests that the protostylid represents a fairly young specialization and a last product of the buccal cingulum.
3. On the enamel-dentin border, the tip of the metaconid and the protoconid may be connected by the so-called distal trigonid crest. The distal trigonid crest was originally reported by WEIDENREICH (1937), who found this crest in the deciduous lower second molar of Sinanthropus. It is very probable that this crest has reduced from fairly early times in the course of human evolution. The frequencies of this crest on enamel-dentin border are 46.4% in Mr and 20.8% in M2. However, there are varieties in the type of this crest. We classified the distal trigonid crest (transverse ridge) into five types as shown on figure 11. The percentage frequencies of the transverse ridge are shown in table 8.
4. The sixth cusp is one of the accessory cusps which occasionally appears between the hypoconulid and the entoconid. The percentage frequencies of the sixth cusp on the enamel surface are shown in table 9. On the enamel-dentin border, the sixth cusp is indistinct, while the spine of the occlusal marginal ridge may be present on the place where the sixth cuspshould be.
5. The seventh cusp occasionally appears between the metaconid and the entoconid. It seems to be identical to the tuberculum accessorium mediale internum defined by SELENKA (1898). The percentage frequencies of the seventh cusp on the enamel surface are shown in table 10. On the enamel-dentin border, the seventh cusp is indistinct, while the spine of the occlusal lingual margin may be present on the place where the seventh cusp should be. 6. The A-type of metaconid ridge on enamel-dentin border (Fig. 8), triangular ridge of metaconid and deflecting wrinkle are intimately correlated with one another. There are negative correlations between these three traits and the distal accessory ridge of the metaconid.

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