The eruption-wear patterns of mandibular teeth from over 500 Japanese serows, Capricornis crispus, were compared with ages determined by annulation in horns and teeth. Ages can be determined by eruption and replacement of the teeth up to about 31 months. Age estimation by visual and quantitative examination of tooth wear patterns is valuable with some limitations. There is no significant difference in the degree of wear between sexes. The timing of completion of permanent dentition in this species is earlier than that of other bovids.

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The reproduction and longevity of the feral house mouse, Mus musculus molossinus, were compared between an island (Saku Island, Mikawa Bay, Aichi Prefecture) and the mainland (Kasugai and Nagoya Cities, Aichi Prefecture) . As compared with the mainland populations, the island mice showed the following characteristics: 1) No spring reproduction. 2) Delayed maturation of females; in particular, females born after January would not produce young until the following autumn. 3) Low proportion of fertile males and pregnant or lactating females. 4) Skewness toward old ages of females participating in reproduction; this is especially conspicuous in autumn. 5) A similarity in number of embryos. 6) Great longevity of adults. 7) About equal mortality in young (the age group 0) . 8) Light wounding. Most of these parameters indicate that the island mice are K-selected, which selection seems to favor lower reproduction and greater longevity for Saku Island mice.

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All the specimens of the Japanese water shrew, Chimarrogale himalayica platycephala, from Kyushu used in this study were obtained at the sides along clear streams less than 5 m in width in mountain districts, and its population size indicated an apparent decline. The body weight, external and cranial measurements of our 11 specimens (6 males and 5 females) and 4 individuals by YOSHIDA (1968) from Kyushu were compared with 43 individuals by FUZIWARA (1958), IMAIZUMI (1960) and ABE (1967) from Honshu. The female was smaller than the male and both sexes in Kyushu showed a tendency to be smaller than those in Honshu. Furthermore, as the result of a comparison of the size among the individuals from Honshu and Kyushu, those from Nepal by ABE (1971), and those from Fukien and Taiwan (including our 1 male) by JONES & MUMFORD (1971), this species shows a trend to become gradually larger from south toward north. The phenomenon that the shrew in Kyushu is smaller than that in Honshu is considered to be a representation of this cline.

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The chromosomes of the Japanese grass vole, Microtus m. montebelli, were examined in detail by G-, C- and N-banding methods, paying special attention to the karyotypic comparison with the root vole, Microtus oeconomus studied by FREDGA et al. (1980) .
Interspecific comparison of G-, C- and N-bands confirmed that 1) both species show almost perfect G-band homology in all the chromosomes, excluding the pericentromeric region of the X chromosome, which is also the case with the C-banding patterns, 2) the X chromosome of the Japanese grass vole is 1.7 times as large as that of the root vole: this is attributable to the difference in the size of C-band material, and 3) the distribution pattern of NORs differs completely between the two species; and the discrepancy seems to be caused by translocation and inactivation of NORs.
Thus, it is suggested that the Japanese grass vole is closely related, in karyological and systematic aspects, to the root vole, and further that duplication of C-heterochromatin and translocation and/or inactivation of NORs might have played a role in the speciation process of these two microtine species.

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Diagnostic characters of the mammae and bacula between E. smithi and E. kageus were studied in specimens of 47 females and 71 males collected from five localities in Honshu and one in Shikoku, Japan. The specimens of each locality are composed of pregnant females, postpartum (non-pregnant) females with the open pubic symphysis, and males with the baculum in which three digital processes fully ossified.
Lack of the right or left pectoral nipple, and a small pectoral nipple on both sides or either side were found in nine specimens at four localities. Females with a normal-sized pectoral nipple on both sides were collected together with ones lacking it on both sides at three localities. The variation of the pectoral nipples in the females with the open pubic symphysis seems greater under postpartum conditions than in pregnancy. Mammary glands were absent in the pectoral part of all females examined, although present in the inguinal part.
Two-way table of the baculum characters showed independency between the contour types on the posterior border of the stalk and on the inner side of the lateral digital process, and between the contour type on the posterior border and the profile type on the stalk axis at four localities with a large sample size. Also in the frequency of the types of the stalk axis, posterior border and digital process of the baculum, independency existed among six localities. The analysis of variance showed no significant difference in the mean ratio of the baculum width to its stalk length among six localities.
Therefore, it is impossible to distinguish E. kageus from E. smithi by these diagnostic characters. Furthermore, I argue that it is difficult to accept the establishment of E. kageus using the method of coefficient difference.

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