Ten percent of male habu, Trimeresurus flavoviridis, larger than 75cm in snout-vent length (SVL), eject a creamy white material from the vent during the measurement of SVL. The frequencies of ejection were high in April and May and low from July to September, and might be used as indicators of the maturity of male snakes and of the mating season.

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Eighteen live and 51 stuffed hawksbill turtles, Eretmochelys imbricata, from the Yaeyama Islands had the standard carapace length ranging from 289mm to 820mm with a mode in the size class of 440-460mm, and were distinctly larger than turtles from Sumatra presented in the literature. Of the fifteen live turtles released from Kuroshima, six were recaptured, five of which in turn were recaptured in the waters adjacent to the Yaeyama Islands within 13 months; the remaining one was recaptured in the coastal waters of Okinawajima Island. On the basis of the size composition and recapture data, problems of life history and conservation in this species are discussed.

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Gonadal development was studied histologically in Onychodactylus japonicus, and changes in the number of germ cells in the course of sex differentiation were examined. The mode of sex differentiation is of the sexually differentiated type. Gonadal sex differentiation occurred directly from the sexually indifferent primordial gonad, and this differentiation was recognized in the larvae of 19-22mm in snoutvent length (developmental stages 67-68). Slight local variations in external and histological structures were observed in the primordial gonad. No sexual difference in the number of germ cells was found when sexual differentiation was beginning. Just after sex differentiation, secondary oogonia appeared in the ovarian primordia, and proliferated temporarily. Germ cells in the ovarian primordia therefore became more numerous than those in the testicular primordia. When auxocytes appeared in the ovaries, oocytes in earlier stages decreased in number, and degenerative germ cells were seen. In the testes, a positive correlation was recognized between the number of germ cells and body length.

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Sexual size dimorphism was examined for five species of flying lizards, genus Draco, from Southeast Asia. Female SVL was larger than male SVL in three species. This sexual size dimorphism may be related to differences in gliding performance between males and females. Quantitative characters of wings such as wing shape and wing loading were compared between the sexes within each species. Significant sexual dimorphism was found in five characters.

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The reproductive behavior of the Japanese salamander, Hynobius retardatus, was observed in the laboratory. The sequence of reproductive behavior was: 1) males grasped twigs in the water and the female hid herself beneath a broad leaf on the bottom, 2) the female began to swim restlessly, 3) males turned their heads to ward the female, 4) the female grasped the twig, 5) the female pressed her vent against the twig, 6) males turned their heads toward the female's vent, 7) the female rubbed her vent over the twig, 8) males brought their snouts close to the female's vent, 9) the female elevated her tail, 10) the male grasping the upper position of the twig held the female's waist, 11) the female began egg-sac laying, 12) the male pulled egg sacs out of the female's vent, 13) other males began to scramble for egg sacs, 14) the female fell to the bottom and hid herself beneath a leaf, 15) males ceased to hold egg sacs, and 16) males paid no attention to the egg sacs. On an average, the males required 571.3 sec for the behaviors from 3 to 15, and the females required 68.5 sec for the behaviors from 4 to 14.

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The annual activity and home range of the Japanese pond turtle, Mauremys japonica, were investigated from 1985 to 1990 in the northern part of Mie Prefecture by means of mark-recapture and radio-telemetry. The turtles lived mainly in paddies from May to August when paddies were irrigated. When the irrigation period was over, however, the main habitat of the turtles changed from paddies to brooks and ponds from September to April of the following year. Females were captured more frequently than males in the irrigation period, whereas males were found more frequently in the non-irrigation period. In the mating season, mainly from September to April, males walked around more frequently and were active at lower water temperature than females. The mean home range size in the brook was estimated to be 99m in males and 40m in females by means of radio-tracking, and 71m in males and 47m in females by mark recapture. The higher activity and larger home range of males during the period from fall to spring of the following year are attributed to active searching for stationary females by males.

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