An extinct proboscidean incisor (INM-4-013796: Kitashiogo C specimen, Ibaraki Nature Museum) was discovered in Miocene sediment near Hitachiomiya City, Ibaraki Prefecture, Japan in 1978. A narrow enamel band extended along the lateral surface of the incisor. The incisor enamel of living elephants is difficult to study because it is lost early after the eruption, and histological reports of fossil proboscidean incisors are rare. As for cementum, there have been reported many studies of coronal cementum on molars, but few studies of cementum covering incisors. In this study, we report on the fungiform cross-sectional morphology of the enamel band of the incisor, including the irregular Hunter-Schreger band and the arcaded to keyhole type enamel prism. We then reveal the presence of the cementum covering the enamel band and describe the histology of the cellular cementum. And the cementoenamel junction is analyzed to indicate different patterns of smoothness and limited resorption. Although this incisor may belonged to a Stegolophodon sp. because of the estimated location and the similar proboscidean fossils excavated in the vicinity, it should be prudent to identify its classification from a histological point of view until it is compared with a confirmed specimen.

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 In 1930 and 1933, fossils of Naumann’s elephant (Palaeoloxodon naumanni) were excavated from the site of the Bank of Japan Head Office (Nihonbashi Hongokucho 2-chome, Chuo-ku, Tokyo), and reported by Tokunaga (1933). These fossils are still strictly the property of the bank. This paper presents the results of a re-examination of the fossils and reports new findings.  Among the fossils reported by Tokunaga (1933), a tusk, right mandible, right upper molar and tibia were unable to be located, but 17 pieces, including a left mandible, right upper molar, fragments of ribs, scapular fragments, humerus and femur, were available for re-examination. The stratigraphic level is the lower part of the Tokyo Formation (Port of Tokyo Geological Reseach Group, 2000), there are various views on the era, MIS 8-5. According to Tokunaga (1933), there was a four meters difference in depth between where the tusk was found in 1930 and the other elephant fossils found in 1933. However, the results of the re-examination show that the stratigraphy is almost the same horizon.  Tokunaga (1933) treated the tusk, upper molars, and mandible with molars as they were from different species, although the tooth type of the upper and lower molar is the same as the well-worn third molar. Additionally, their occlusion matches very well, the sizes of all the fossils are rather small for a Naumann’s elephant and totally balanced, and no parts overlap, suggesting that they are from the same individual.  The size of this specimen is rather small or middle for Naumann's elephants, and it could be the one of MIS 5 according to the view of Kondo (2005). The discussion about the size differences by age would be required after the age of Tokyo Formation is determined.

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