Final answer:
Podocytes interdigitate to form filtration slits in the glomerular capsule.
Step-by-step explanation:
The structures in the glomerular capsule that interdigitate to form filtration slits are podocytes. Podocytes are cells with finger-like processes that form the visceral layer of Bowman's capsule. The finger-like extensions of the podocytes, called pedicels, interdigitate with each other to create filtration slits, which allow substances to filter based on size.