1. Amphids (Greek: amphi, around, double) are innervated invaginations of cuticle in nematodes

2. The inner mitochondrial membrane creates tubular invaginations, what experts call cristae.

3. The tentorium forms during development when pairs of Apophyses (finger-like invaginations of exoskeleton) fuse internally to create a "bridge"

4. This osmiophilic layer, about 250 Å in diameter, forms numerous villus-like folds and vesicle-like invaginations into the interior of the cyst.

5. The tube-like invaginations exist only for a few minutes. The ingestion of cell membrane at the caudal pole of A. proteus is bound to the amoeboid movement.