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. 



B. 



FIG. 35 LARVAL STAGES OF THE COMMON ROCK BARNACLE 

 (Balanus 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- 



