DORIS TUBERCULATA. 



distinct from ours. We think that the Doris tuberculata of Loven, found on the Norwegian 

 shores, is also probably distinct, though very nearly allied to our species. 



Figs. 1, 2. Side and back views of Doris tuberculata. 



3. Anterior portion of the underside. 



4. Side view of tentacle. 



5. Enlarged view of portion of a branchial plume. 



6. A portion of the mantle enlarged, showing the tubercles. 



7. Spawn. 



8. A portion of the same enlarged, showing imbedded ova. 



9. One of the ova much enlarged : — a, yolk ; b, corion. 



10, 11, 12, 13, 14, 15. Embryos, showing progressive development: — b, corion; c, shell; 



d, operculum ; e, foot ; /, oral lobes ; g, mouth ; h, stomach ; i, intestine ; j, liver ; 



k, reproductive organs ; /, otolithes ; m, membranous envelope ; n, muscle attaching the 



embryo to the shell. 

 16. Spicula from the cloak. 



