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单词 cloaca
释义

cloaca

/kləʊˈeɪkə /
noun (plural cloacae /klsiːʊˈeɪkə/ /kləʊˈeɪkiː/)
1 Zoology A common cavity at the end of the digestive tract for the release of both excretory and genital products in vertebrates (except most mammals) and certain invertebrates.Instead, males deposit spermatophores on the substrate and females pick up these spermatophores with their cloaca later....
  • After males deposit spermatophores onto the cloaca of females, up to 150 eggs are laid on mud near water.
  • Unlike we humans, the chicken has a single sexual and excretory orifice, the cloaca.
2 archaic A sewer.The cloaca maxima was the sewer system built in the sixth or seventh century BC, by one of the kings of Rome.

Derivatives

cloacal

adjective ...
  • A current theory is that the eggs are ovulated through the cloacal pore and are expelled under pressure by muscular contractions.
  • Bird penile tissue, where it exists, also develops on the ventral cloacal wall.
  • Little is known of their reproductive biology, but the lack of both spermatheca in females, and cloacal glands in males, suggests external fertilization.

Origin

Late 16th century (in the sense 'sewer'): from Latin, related to cluere 'cleanse'. The first sense dates from the mid 19th century.

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更新时间:2024/11/11 7:18:31