This beautiful egg donated by Florida Fan nicely demonstrates all of the classic features of H. nana, including the thin inner membrane surrounding the hooked oncosphere [*] from which polar filaments arise. The polar filaments arise from opposite poles of the inner membrane (arrows) and spread out into the space between the inner and outer membranes, thus providing a key differentiating feature from the filamentless-Hymenolepis diminuta.
There once was a kid from Indiana
Who with his oatmeal did like banana
But with his food he did eat
A most wonderful treat
The cestode known as Hymenolepis nana
If you google "oatmeal" and "bugs," you will find multiple consumer complaints (and some nice YouTube videos) to explain the oatmeal reference!