In the Eastern/Southeastern Pacific, four species are recognized within the genus Limacia. One species occurs in Chile and second, tropical one that ranges from Baja California to Panama.
Here are the other two:

Limacia cockerelli: Originally found from Ketchican, Alaska to Point Loma, San Diego, but now it is common only in the northern part of its range. The dorsum has numerous small, scattered white tubercles, which may also have a central orange-red spot. The gill is white and may have red tips. Rhinophoral clubs are bright red.

Previously classified as Limacia cockerelli, Limacia mcdonaldi has been shown to be a separate species: It occurs from Northern California to Baja California, but is most common in SoCal and Northern Mexico. The dorsum is smooth, but decorated with a single row of orange-red tubercles. Rhinophoral clubs are orange-red.

Their ranges overlap from Salt Point in Sonoma County to San Diego, but it appears that L. mcdonaldi is more abundant in the southern portion of the overlap. We had to go all the way to British Columbia to see our first L. cockerelli.

Full text with more photos may be downloaded at the link.

• https://www.researchgate.net/publication/315157046_Integrative_systematics_of_the_genus_Limacia_O_F_Muller_1781_Gastropoda_Heterobranchia_Nudibranchia_Polyceridae_in_the_Eastern_Pacific