The image presents Hydra with numerous testis. It is ready to sexual reproduction. Magnification is 25X. Technique of the illumination: dark field and polarized light.
<a href="//commons.wikimedia.org/wiki/User:MarekMi%C5%9B" title="User:MarekMiś">MarekMiś</a>
CC BY 4.0
<span class="int-own-work" lang="en">Own work</span>