Dr Bather justifiably anticipates further discoveries, but if, already in Silurian as in modern times, the members of these families had to pass through nauplius and cypris stages to maturity, there is one " enormous gap " between them and the common ancestor of the crustacean class that will not be easily filled.
Though the Ornitholepas australis (Targioni Tozzetti, 1872), found on the tail feathers of a bird, represents only the cypris-larva of a cirripede, it still shows one of the many facilities for dispersion which these creatures enjoy.
The student may then be asked to compare the account of Synagoga mira both with the figure of the cyprisstage of Dendrogaster astericola and with the figure of the " indeterminate animal found on Gerardia," about which Lacaze-Duthiers asks, " Is it the cypris-stage of Laura?"
Its six pairs of limbs are not like the bare and simple feet of the Laura, but two-branched and setose as in the ordinary cypris-stage of the cirripede.
Mira is either the cypris-stage of Laura gerardiae or of some congeneric species.