Sea Lemon   Doris (Archidoris) montereyensis

One of the largest sea slugs, or more properly nudibranch (meaning “naked gills”), the Sea Lemon can be found in the low intertidal and subtidal zones. There are several other similar yellow to orange species which differ in size and body color pattern. 

While it’s average size is in the four inch range (as is this specimen) , it can grow to 6 inches.  It is usually a bright yellow to orange in color with black spots both between as well as on the tubercles (small body projections).  It has two upright structures (rhinophores) on the head (withdrawn on the left of this animal) used to detect water-born smells and a frilly ring of light yellow to orange respiratory gills at the rear which can also be withdrawn. 

The sea lemon feeds on  several kinds of sponge.  Strings of eggs are deposited in the spring.  This species, along with some of its cousins, has an fruity odor which may be a defense mechanism.  The Sea Lemon ranges from Alaska to southern California. 

In Puget Sound there is a wide variety ( around 120 species) of shell-less snails called sea slugs.  Many are very colorful and often standout against the background and are often referred to as marine butterflies.  The gaudy colors are thought to be a visual signal to predators that the animal is not good to eat due to chemical defenses or the presence of stinging cells in those species of sea slug that feeds on hydroids.