THE METAMORPHOSES OF CRUSTACEA 83 



interest, since it was the discovery of the larval 

 stages by J. Vaughan Thompson that first demon- 

 strated to naturalists that the Barnacles were 

 Crustacea and not, as had been supposed. Molluscs. 



Fig. 35 — Larval Stages of the Common Rock Barnacle 

 {Balanns balanoides — see Plate III.) 



A, Nauplius stage (after Hoek) ; B, cypris stage (after 

 Spence Bate) 



The earliest stage is generally a nauplius (Fig. 35, A) 

 of very peculiar and characteristic form, with a pair 

 of horns projecting sideways from the front corners 

 of the dorsal shield, and a forked spine on the under- 



