The first zoeal stage of Eualus sinensis (Yu, 1931) (Decapoda, Caridea, Hippolytidae), with a key to the known Hippolytid first zoeae of Korea and adjacent waters

The first zoeal stage of Eualus sinensis (Yu, 1931) is described and illust rated in detail. The presence or absence of a posterolateral spine on abdom inal somite 5 can be used to separate the larvae of Eualus into two groups. The first zoea of E. sinensis is easily distinguished from that of E. lept ognathus by the absence of a rostrum, a pterygostomial spine. and anteroven tral denticles on the carapace, as well as by the rudiments of pereiopods. A key to the known first zoeae of 20 hippolytid species of Korea and adjace nt waters is provided.