While I haven't read Freud's paper [0] myself, and I know that there are a couple of pop history/science accounts that say that [1], there are also a bunch that

While I haven't read Freud's paper [0] myself, and I know that there are a couple of pop history/science accounts that say that [1], there are also a bunch that don't [2]. A bit of googling drags up this account by a guy who seems to have actually read the paper: >In 1874 Dr. Syrski had announced the most recent solution. He had discovered a small lobed organ and described it as the testes of the eel. Carl Friedrich Claus, chief of the Institute for Comparative Anatomy in Vienna, assigned to his student Freud the task of checking Syrski's observations. Freud dissected 400 eels, finding the Syrski organ in many of them. On microscopic examination he found the histological structure of the organ such that it could well be an immature form of the testes, though he found no definite evidence that this was the case. [3] Modern researchers propose that Syrski's organ is an optional precursor to the testes [4]. [0] For the German readers among us who wish to settle this debate decisively https://archive.org/stream/sitzungsberichte75kais#page/n367/mode/2up https://archive.org/stream/sitzungsberichte75kais#page/n367/... [1] https://www.historytoday.com/archive/natural-histories/sexual-eeling https://www.historytoday.com/archive/natural-histories/sexua... https://biodiversity.utexas.edu/news/entry/sigmund-and-his-eels https://biodiversity.utexas.edu/news/entry/sigmund-and-his-e... [2] http://nautil.us/issue/88/love--sex/eels-dont-have-sex-until-the-last-year-of-their-life http://nautil.us/issue/88/love--sex/eels-dont-have-sex-until... (an interview with the author of TFA) https://twitter.com/greenleejw/status/1205524393490833408 https://twitter.com/greenleejw/status/1205524393490833408 (This is where I originally picked up the fact, strongly recommend you follow if you have even a passing interest in medieval eel facts) [3] https://www.jstor.org/stable/26301225 https://www.jstor.org/stable/26301225 [4] https://www.researchgate.net/profile/Benjamin_Geffroy2/publication/234702131_New_insights_regarding_gonad_development_in_European_eel_Evidence_for_a_direct_ovarian_differentiation/links/0046352dd36f7af8ad000000.pdf https://www.researchgate.net/profile/Benjamin_Geffroy2/publi... (pdf)