A 'Hinnites' species from Ogasawara Islands, Japan, hitherto identified with Hinnites corallinus Sowerby, 1827 is different from the west African species H. corallinus and is new to science. Therefore, we describe the species under the name of Chlamys ('Hinnites') boninensis. Chlamys ('Hinnites') boninensis Dijkstra and Matsukuma, n. sp. Cemented on a colony of coral Montipora in 10 m deep. Shell medium, approximately 42 mm in height, thin. Juvenile Chlamys-stage 16-21 mm high. In left valve, anterior and posterior auricles nearly equal in size, ornamented with a shagreen microsculpture. Outer surface of both valves ornamented with Camptonectes microsculpture. Type locality : Chichijima Island, Ogasawara Islands (lat. 27°N, long. 142°E). Typology : All type materials stored in National Science Museum, Tokyo. Holotype, NSMT-Mo 69619 ; paratypes, NSMT-Mo 69622 to 69624. Remarks : The new species differs from the following species by the possession of thinner shell with the shagreen microsculpture : Hinnites corallinus, H. absconditus from western Africa, and Crassadoma gigantea from the northeastern Pacific. These three species have thicker and larger shells, occasionally exceeding 140 mm in height, and lack the shagreen sculpture. Although this new species differs from Australasian Eocene to Miocene 'Hinnites' species in shell shape, the shagreen sculpture is a characteristic common to Japanese and Australasian species.

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The investigations on shell and anatomical characters on "Collisella" oyamai Habe, 1955 revealed that it should be placed in the subfamily Patelloidinae of the Lottiidae and need a new genus, Yayoiacmea. Of systematic characters of the new genus, the radula teeth morphology is unique among the known members of the family.

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A large-sized lamellariid, Onchidiopsis nihonkaiensis n. sp. collected from deep waters in Ryotsu Cove, Sado Island, the Sea of Japan is described. This species is characterized in having an oval gelatinous body spotted by white on black dorsal mantle in which a large, shallow, transparent, oblong oval shell with rudimentary spire. This is the second species of this genus hitherto known from Japanese fauna.

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Both Eosipho boucheti n. sp. and Phymorhynchus wareni n. sp. were collected from North Fiji Basin and Lau Basin where active hydrothermal vents exist. The former species are so abundant that it is hardly a mere guest species to the vent areas but has a certain relation to the vent biocommunity, while the latter may be a guest which may live in non-vent areas as well.

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This paper describes two new species of Carminodoris, C. armata n. sp. and C. bifurcata n. sp., from Japan. Both species have penial armature.

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A new genus Danjochlamys typifying Danjochlamys meshimaensis n. sp. from Meshima, Danjo-Gunto, Nagasaki Pref., Kyushu, is proposed based upon genitalia morphology, such as an absence of the flagellum.

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The reproductive system, radula and clausilium of H. myersi is reported for the first time. The result is compared with Euphaedusa sheridani (Pfeiffer), Hemiphaedusa magaensis Chang, Hemiphaedusa bagsana (Schmacker and Boettger) for considering its systematic position.

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The chromosomes of Dentalium octangulatum and Fissidentalium (Pictodentalium) vernedei were studied. Chromosome numbers and karyotypes of these species were as follows : D. octangulatum (2 n=20) : 6 m+14t, NF=26 F. (P.) vernedei (2 n=20) : 8 m-sm+12 t, NF=28

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Delayed inheritance is often confusingly described in Japanese textbooks of genetics : 1) Delayed inheritance of shell chirality is introduced with a Japanese name of Lymnaea japonica, although it has not been confirmed in Lymnaea except for L. peregra. 2) The mode of chirality inheritance tends to be called maternal inheritence, because of historical reasons. Maternal inheritance was first defined by Toyama (1913) as the mode of inheritance observed for serosa color of eggs of the domesticated silkmoth, Bombyx mori. The results of breeding experiments have evidenced his interpretation that maternal inheritance is a Mendelian mode of inheritance, which was later named delayed inheritance by Boycott et al. (1930). Although Boycott and Diver (1923) first reported the inheritance of shell coiling in Lymnaea peregra, it was Sturtevant (1923) who indicated that their results can be explained by maternal inheritance. According to his statement, Sturtevant (1923) apparently had accepted the term defined by Toyama (1913). However, Sturtevant and Beadle (1939) ignored the definition of both maternal inheritance and delayed inheritance and used maternal effect to refer to the inheritance of coiling chirality in L. peregra. Since then, maternal inheritance has been used as the equivalent to cytoplasmic inheritance, outside Japan. Today in genetics, maternal inheritance is commonly understood as cytoplasmic inheritance, even by Japanese geneticists. Then the mode of chirality inheritance should be distinguished from maternal inheritance in textbooks as well. However, it should be also noted as a historical fact that maternal inheritance was originally defined by Toyama (1913) to indicate the mode of delayed inheritance.

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