In Lepas fascicularis the earliest free nauplius is enveloped in a larval skin, which is thrown off after a few hours.
The young barnacle, called a nauplius, in no way resembles the adult.
Only the embryos of Leptodora are known to hatch out in the nauplius stage.
But instead of rising to its opportunities, the sacculine nauplius having reached a certain point turned back.
Two lateral compound stalked eyes are present, together with a median nauplius eye.
There spring from it the three typical pairs of nauplius appendages.
But of all living crabs the Phyllopods are the most closely allied to the original primary form of the nauplius.
It is also found in the earliest and most primitive form of larva, known as the nauplius.
From the nauplius condition the larv pass at a single moult into an entirely different condition known as the Cypris stage.
This is well seen in the nauplius of many Cirripedia (fig. 15) and in nearly all zoeae.