ウ

科二枚貝ベッコウマメアゲマキScintilla philippinensis Deshayes, 1856の生体がフィリピン・パラワン島で採集されたが，外套膜とその膜上の突起，足を用いてウミウシ類及びカニ類に擬態と考えられる行動が観察された。ウミウシ類型の場合，外套膜を変形させて形態を似せる。カニ類型の場合には形態的類似性だけでなく足も用いて行動も真似る。ウ上科は他の動物に共生することで知られるが，擬態に関する知見は少ないので，今後のより詳細な研究が待たれる。

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A new species of the galeommatoidean bivalve is described from Okinawa Island, East China Sea. Ephippodonta gigas n. sp. belongs to the subgenus Ephippodonta Tate, 1889 with cardinal tooth and plain inner margin. This species has a large shell with the glossy surface and differs morphologically from all of its congeners.

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The present study deals with the anatomy of Semisulcospira bensoni. Though the shells of this feesh-water snail are sexually indiscriminate, the female snail is easily distinguished from the male by the presence of the brood pouch, and by the difference in shape between the testis and ovary in breeding season. The excretory opening of the kidney is situated at the apicalmost part of the mantle cavity and the excretion is carried by the exhalant ciliary current observed on the outside of the prostate gland in male or of the accessory gland and brood pouch in female. The male copulatory organ was not defined. The arteries are feebly developed, while the sinus are well developed, being dark green in colour due to the presence of haemocyanin. The central nervous system is composed of 11 ganglia, and the connectives between them are long, above all, that between the right pleural and supra-oesophageal ganglia being longest. The visceral ganglion is composed of 2 lobes. The stomach consists of 2 parts of lumen, the anterior of which has many complicated muscular folds on the inner surface and the posterior is dorsoventrally divided by typhlosoles into the crystalline style sac and intestine.

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Morphological and genetic traits of Lingula adamsi were compared among individuals from South Korea (Yellow Sea) and Japan (Ariake Sea). The Japanese population is usually identified as L. shantungensis, although this nominal species has been placed in synonymy with L. adamsi. Some studies have suggested that the Japanese population is a different species or subspecies from L. adamsi based on morphological comparisons. In this study, morphological characters of the shell of ten individuals of L. adamsi collected from southwestern South Korea, such as shape, color, and surface ornamentation, were compared with those of the Japanese population. Although the width/length ratio of the dorsal shell is significantly different between the South Korean and Japanese samples, this and all other morphological differences can be considered as intraspecific variation. The nucleotide sequences of the mitochondrial coxl gene region indicate a very low level of variation between the ten South Korean individuals and an individual from the Ariake Sea, Japan, not greater than that observed within local populations of Lingula anatina. The forms from South Korea and Japan, therefore, are best interpreted as conspecific from the viewpoint of both morphological and genetic variation.

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がんは，昭和56年から現在に至るまで日本人の死因の第一位となっている．がんの治療・治癒には早期発見が最重要であり，簡便に検査でき，高精度でがんを検出する方法が求められている．現在，がんの検出方法は，液体クロマトグラフ装置等を用いて患者の血液・尿からがんを特定可能な有機化合物（以下，腫瘍マーカ）の含有量が基準値を外れた場合に，がんを疑い病理検査等で，数日を要してがんの有無を判断する．本研究では，簡便に採取できる尿中に存在する腫瘍マーカのホモバニリン酸に着目し，短時間で検出可能な表面プラズモン共鳴（SPR）センサと抗原抗体反応を組み合わせて検出を試みた．

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Peregrinamor ohshimai is a symbiotic bivalve associated with upogebiid mud shrimp, typically distributed along the Pacific coast of Japan, from Ibaraki Prefecture to Kumamoto Prefecture. During a survey conducted by high school students, a specimen of P. ohshimai was found attached to Upogebia yokoyai in Shizugawa Bay, Miyagi Prefecture. This finding extends the known distribution of P. ohshimai to northern Japan.

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オサガニヤドリガイ(新称=Pseudopythina macrophthalmensis Morton and Scott 1989)はホンコンを模式産地として記載されたウ超科の二枚貝である。この貝は, 干潟に生息するスナガニ科の一種ノコハオサガニの体表に多数着生した状態で採集されたが, 採集例はその一例のみでその後ホンコンでも採集されていない。今回, 沖縄県西表島船浦の干潟で, フタバオサガニの体表よりこの貝を多数採集したので, 日本初記録として, またカニに付着して生活するという特異な生態に関して得られた知見について報告する。船浦で採集したフタバオサガニ65個体中51個体にオサガニヤドリガイが着生していた。船浦のほか, 西表島仲間川ではフタバオサガニに付いたオサガニヤドリガイを確認できたが, 沖縄島では2地点のフタバオサガニ個体群について調査したものの貝は採集されなかった。一方タイ南部のプーケットでは, やはりフタバオサガニに付いた状態の同種を確認しており, オサガニヤドリガイの分布域はインドー西太平洋の亜熱帯, 熱帯域に広がっていることが明らかになった。一旦カニから外したオサガニヤドリガイを一晩カニとともに飼育したところ半数以上の貝が再びカニに付着していた。このことは, カニの脱皮殻と共に貝がカニの体から離れても, 再びカニの体表に付着する能力を備えていることを示している。

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