i spermatozoid

[Mod. Lat. spermatozo( on ), and Gr. eidos =form, resemblance. (See def.)] Biol.: Von Siebold's name for a spermatozoon (q. v.). Dunglison (ed. 1874) says: "More properly, demonstrated." The name also applied to anther spermatozoid, for their animalcular nature is not ozoõids. [ANTHEROZOÕID.] spēr-ma-to-zō-on ( pl. spēr-ma-to-zō-a), s. [Pref. sperm a to-, and Gr. zōon =an animal.] Biology ( pl .): The name given by Leeuwenhoek to the moving, active constituents of the seminal fluid, which were brought to his notice by his pupil Hamm, in 1677. Spermatozoa consist of a head, a rod-shaped middle piece, and a long hair-like tail, by the vibratile motion of which they move in a spiral manner. Cold arrests their movements, and they may be deprived of vitality (the power of fecundation) in various ways. They were at first regarded as parasites, and cla ified as Helminthes or Infusoria, and Von Baer maintained this view as late as 1835. Von Siebold discovered them in many vertebrates, but Kõlliker was the first to rесognize them as definite histological elements arising within the testes. [SPERMATOZOID.]