I recently made the (possibly useless) discovery that the vast majority of names for shelled mollusks don't actually contain the 貝 primitive as a sub unit (though many contain the unembellished 貝 character as a suffix).

The following are all names for various types of 貝:

浅蜊
蛤
栄螺
鮑
牡蠣
蝸牛
蛞蝓
蜆
玉珧
田螺
蛽 (with alternate spellings 海蠃 and 海螄)
雨降

Just thought I'd share with everyone.

貝 is apparently just a specific type of shellfish (bivalve). I've always sucked at flora & fauna names though.

Indeed. 虫 seems to be the general primitive for all the creepy crawlies. 貝 is more often used in money related kanji.

虫 was apparently originally just for classifications of animal types, while 蟲 meant what we typically think of as a bug.

Quote:名}動物の総称。羽虫は鳥類、毛虫は獣類、甲虫は亀カメ類、鱗虫（リンチュウ）は魚類、裸虫は人類のこと。

Jarvik7 Wrote:貝 is apparently just a specific type of shellfish (bivalve).

I don't think this is true. I think any mollusk with a shell (and possibly some without) would be considered 貝. (c.f. 巻貝) If that weren't the case, they wouldn't need to qualify the word to get the term 二枚貝.

Quote:二つにわれるかい。のち転じて、かいの総称

The term has been seemingly generalized, but its etymology suggests why few shellfish names contain the character.