61. A sea slug, Okenia qiiadiicomis, 

 with a tuft of gills near the rear end. 

 Like other sea slugs, it has a larval 

 shell, which later disappears. (Eng- 

 land. D. P. Wilson) 



64. Two members of the species shown in Plate 62 here 

 display their opalescence and their two pairs of tentacles 

 as they feed on a hydroid colony. Common on mud flats 

 but also on rocks or pilings. (California. Woody \\'illiams) 



62. One of the commonest sea slugs 

 on the American Pacific coast is 

 Hermissenda crassicornis, with tufts 

 of gill-like extensions on the back. 

 It is usually colored as shown here, 

 but the color may vary. (Oregon. 

 Ralph Buchsbaum ) 



63. Its coloring and the branching processes make Dendmnotiis froitdosus, a 

 sea slug 2 to 3 inches long, hard to detect when it crawls among seaweeds. It 

 often feeds on Tiihidaiia (Plate 5). Distributed on northern shores around the 

 world. (England. D. P. Wilson) 



