Kiphonautes larva - Kiphonautes larva

Japanese: キフォナウテス幼生 - きふぉなうてすようせい

… They are hermaphroditic and reproduce sexually by hatching from eggs, and asexually by budding. Most are fertilized internally, where they develop and hatch into trochophoran larvae or kyphonautes larvae with two triangular shells, which live in the plankton. Trochophoran larvae attach to other objects after a few hours, and kyphonautes larvae attach after about 10 days to a month, metamorphosing and calcifying, and then budding to produce new individual larvae and grow the colony. …

From [Tentacle Animals]

...Hermaphrodite. It produces larvae called cyphonautes. It is considered a fouling organism because it attaches to and harms various organisms and facilities.

*Some of the terminology explanations that mention "Kyphonautes larva" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…　雌雄同体で卵から孵化（ふか）する有性生殖と出芽によって増える無性生殖とを行う。大部分は体内で受精し，そこで発生が進んで孵化し，トロコフォラ幼生や三角形の2枚の殻をもったキフォナウテス幼生となり，プランクトン生活をする。トロコフォラ幼生は数時間，キフォナウテス幼生は十数日～1ヵ月後に他物に着生し，変態して石灰化し，のち出芽によってどんどん新しい個虫を増やして群体を大きくしていく。…