66 )S. I^. (J lark on New and Rare ISpedes of Hydroids. 



Plate X. 



Figure 1. Galycella syringa ; from Casco Bay, showing a peculiar variation in the 

 operculum. 



Figure 2. The same, showing the variation in the size and shape of the hydrotheeas 

 and in the length of the pedicel. 



Figure 3. The same, with one secondary ring. 



Figure 4. Clytia Johnstoni, from Noank, Conn. 



Figure 5. Campanularia noliformis, showing variations in the pedicels. 



Figure 6. Halecium articulosum ; from Coxe's Ledge. A, a branch bearing both 

 hydrothecte and gonothecse ; a, gonothecas ; 6, hydrotheca3. B, a branch with hydro- 

 thecae only ; h, a branchlet ; c, hydrothecis. 



Figure 7. Sertularia argentea, var. diva?-icata ; from Casco Bay. 



Figure 8. Gonothyrcea tenuis ; a, branch with hydrothecae ; h, gonotheca with extra- 

 capsular medusa; ; c, medusa with radiating tubes and tentacles ; d, planulse. 



Figure 9. Plumularia Verrillii; a, branch showing hj^drotheca; and nematophores 

 and the arrangement of the joints ; b, gonotheca ; c, a single joint. 



