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Volume 18, Issue 1
Displaying 1-7 of 7 articles from this issue
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Kouichi Kawaguchi1971 Volume 18 Issue 1 Pages 1-16_3
Published: June 15, 1971
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSEight genera and 15 species of mesopelagic fishes belonging to the family Gonostomatidae are reported from the western North Pacific, based upon the materials collected by research vessels of the Ocean Research Institute, University of Tokyo, during the years 1964 to 1968.Of these, nine species; Pollichthys mauli Grey, Vinciguerria attenuata (Cocco), Gonostoma atlanticum Norman, G.elongatum Günther, Cyclothone alba Brauer, C.pseudopallida Mukhacheva, C.pallida Brauer, C.acclinidens Garman and Valenciennellus tripunctulatus (Esmark), are new to the Japanese fauna.Keys to each genus and species, and some systematic accounts are presented except the genus Polymetme.View full abstractDownload PDF (13792K) -
Sachiko Ishida, Mitsuo Sato1971 Volume 18 Issue 1 Pages 17-24
Published: June 15, 1971
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThe supposed similarities between the large pit organ and lateral-line canal organ were confirmed by the present investigation: the receptor cell is provided with sensory hairs which are arranged in a characteristic pattern, described in the receptor cell of the canal organ, and are innervated by two kinds of nerve endings, i.e., nongranulated and granulated, although the former appears more frequently than the latter.The supporting cells which may have sustentacular function and secretory activity are divided into two kinds, the central and peripheral, mainly on the basis of their topographic position in the large pit organ.While these two kinds of the supporting cells show no remarkable differences in their basic structure, the size and shape of secretory granules found in the apical cytoplasm are different between them.Whether such morphological differences of the granules correspond to the differences of chemical natures of substances contained in the granules or not is the subject of future research.View full abstractDownload PDF (10144K) -
Kunio Amaoka1971 Volume 18 Issue 1 Pages 25-32_1
Published: June 15, 1971
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThree postlarvae of the family Bothidae certainly identified as Chascanopsetta lugubris Alcock were obtained from the southwestern area of Japan.They have the following characteristic features: immense size (34 to 120 mm in standard length), elongate second dorsal spine, high dorsal and anal fins, greatly elongate and tapering posterior process of the pelvic bone, the expansion of the intestinal coil beyond the body, and a great number of dorsal and anal fin rays and vertebrae.The species metamorphoses at about 121 to 125 mm in standard length.The relative growth before and after the metamorphic stages, which was observed among several body parts, is divided into two types.The depth of body and the longest dorsal ray make a sudden degression, while the head length, the eye diameter, the pectoral fin length, and the maxillary length show remarkable growth.Probably, the largest of the present specimens, measuring 120 mm in standard length, 135 mm in total length, is the largest larval flounder ever recorded.View full abstractDownload PDF (4734K) -
Ryoichi Arai1971 Volume 18 Issue 1 Pages 33-35
Published: June 15, 1971
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESS -
Yoshiharu Honma, Isamu Ikeda1971 Volume 18 Issue 1 Pages 36-38
Published: June 15, 1971
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESS -
Isao Hayashi1971 Volume 18 Issue 1 Pages 39-50
Published: June 15, 1971
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThe process of the testicular maturation of the Japanese sea bass, Lateolabrax japonicus (Cuvier) has been studied. The testis of this species consists of two parts, the hilus of connective tissue (the mediastinum testis) and the stroma in which many seminiferous tubules are located as in the case of most teleosts. After spawning a seminiferous epithelial cell layer becomes distinct along with the wall of the tubule and develops till appearance of the primary spermatogonia in the tubule. This epithelial cell which is regarded as homologous with the Sertoli's cell seems to have those three important roles: i) the decomposition and the resorption of the remaining sperm cells in various maturation stages in the tubule, ii) the original source of the primary spermatogonia, iii) the nutritional supply to the germ cells. The primary spermatogonia come in sight in the tubule from April to August. After mitoses they change into the secondary spermatogonia in the middle of October. Then they rapidly proceed their maturation processes through the meiotic stages. The spermatozoa appear in the tubule for the first time in the middle of November. Based on the microscopical observation the spawning season of this species is guessed to be those two or three weeks between late December and early January in Wakasa Bay.The seasonal change of gonad index closely reflects the histological maturation process, and is useful for judging the maturity. The male of this species takes two years to mature and the biological minimum size of the male is about 260 mm in standard length.View full abstractDownload PDF (8377K) -
Tadashi Kubota, Teruya Uyeno1971 Volume 18 Issue 1 Pages 51-54
Published: June 15, 1971
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSYoung specimens of Icosteus aenigmaticus Lockington have been reported from several places in Japan.All of these specimens were less than 326 mm in total length and were described as deep-bodied, having blotches on body, pelvic fins, and rounded posterior margin of the caudal fin.The specimen reported here is a mature male collected from Suruga Bay, : Shizuoka Prefecture, on March 15, 1970.The total length is 950 mm.The body color before fixation was dark brown and the pelvic fin is absent.The posterior margin of the caudal fin is lunate.The characters of this specimen match well with those of the specimen described as Acrotus willoughbyi Bean, which has been considered to be a junior synonym of Icosteus aenigmaticus.The appearance of the specimen in Suruga Bay is probably related to the appearance of unusually cold water masses off the coast of southern Japan on the Pacific side.View full abstractDownload PDF (3000K)
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