著者

小林 巌雄

出版者

日本貝類学会

雑誌

貝類学雑誌Venus : the Japanese journal of malacology (ISSN:00423580)

巻号頁・発行日

vol.39, no.3, pp.178-185, 1980-11-30

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The internal shell structure of Bentharca asperula (DALL) is examined under a scanning electron microscope. Living specimens were collected at the sea bottom off Hachijo Island, Tokyo (33°03.5'N ; 140°45.3'E). The shell mainly is composed of outer and inner calcareous shell layers. The former shell layer is made of crossed lamellar structure and the latter is of complex crossed lamellar structure. The crossed lamellar structure of this species is same to the typical crossed lamellar structure of the other Arcoids. Next, there are several different types of the aggregation of crystallites in the complex crossed lamellar structure. The complex crossed lamellar structure of this species is characterized by the parallel arrangement of elongate rod-like crystallites which is inclined toward the ventral margin. Tubules penetrate outer and inner calcareous layers. The openings distribute at the region of inner shell layer on an inner shell surface. The mineral kind of crystallites of both layers is aragonitic crystal. The form of crystallites is elongate rod. The internal shell structure of Bentharca asperula, one of deep sea molluscs, is not special, but is common to one of the other species of Arcoids.