How do crab larvae develop from zoea to megalopa to adult form?

Most decapod crustaceans, including most crabs, bypass the initial nauplius larval stage and hatch directly as zoeae.1

The development process typically follows these stages:

• Zoea: This is an early larval stage characterized by its method of locomotion, as it uses its thoracic limbs for swimming. Crab zoeae are often heavily ornamented with spines.1
• Megalopa (or Megalops): The zoea eventually metamorphoses into a megalopa. This stage resembles a small crab, though it is distinguished by having large eyes and a relatively long abdomen that remains extended behind it. During this phase, the legs and abdominal appendages have appeared.12
• Adult: Following the megalopa stage, the organism undergoes further development to reach its final adult form.1

While this is the general progression for most crabs, development can vary by species; for example, some crabs, such as certain freshwater species, bypass free-living larval stages entirely, with the young emerging from the eggs resembling the adults.1