PZ Myers | Killing a spider stills a beating heart @PZMyersBiology | Uploaded March 2021 | Updated October 2024, 1 week ago.
I'm just always enchanted when I see the hearts of my spiders beating under the microscope.

I explain what you're seeing here:
freethoughtblogs.com/pharyngula/2021/03/30/lab-time-and-a-whatsis