Lingula unguis

Japanese: Lingula unguis（英語表記）Lingulaunguis

...They are found along the coasts south of Honshu, and live by digging vertical holes in the sandy, muddy seabed up to a depth of about 50 meters, with their shells facing up. Many species flourished in the early Paleozoic era, but the only species currently extant are the Midori-shamisengai Lingula unguis (illustration) and 10 others, and they are also called "living fossils." Their bodies consist of two shells in the dorsoventral direction and a fleshy stalk protruding from one end. ...

From 【Brachiopoda】

… As mentioned above, the living brachiopoda are divided into the subclass Inarticulata and the subclass Articulata. The former includes the green-spotted clam Lingula unguis and the anchor clam Craniscus japonicus , while the latter includes the striped clam Terebratulina japonica , the turtle clam Terebratalia coreanica , the striped clam Coptothyris grayi , the clam Laqueus rubellus , and the little clam Pictothyris picta . They live on the seabed at depths of 15 to 500 meters, attached to other objects. …

*Some of the terminology explanations that mention "Lingula unguis" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…本州以南の沿岸に分布し，水深50mくらいまでの砂泥質の海底に垂直に穴を掘って殻を上にして生活する。古生代前期には多くの種類が栄えていたが，現生種はミドリシャミセンガイLingula unguis（イラスト）ほか10種のみで，〈生きている化石〉ともいわれる。体は背腹の方向にある2枚の殻と一端から出る肉質の柄部とからなる。…

【腕足類】より

…　現生の腕足綱は，前述のように無関節亜綱Inarticulataと有関節亜綱Articulataとに分けられる。前者にはミドリシャミセンガイLingula unguis，イカリチョウチンCraniscus japonicusなど，後者にはタテスジチョウチンガイTerebratulina japonica，カメホウズキチョウチンTerebratalia coreanica，タテスジホウズキガイCoptothyris grayi，ホウズキチョウチンLaqueus rubellus，コカメガイPictothyris pictaなどが知られている。水深15～500mの海底で他物に固着して生活している。…