This bright yellow, brown spotted dorid is probably the most common nudibranch seen by PNW snorkelers and tide-poolers alike.  It can get fairly large (up to 15 cm) and it’s not unusual to find them on docks and pilings, or even squished into pockets of water under rock ledges above the low tide line.  The Heath’s Dorid and Noble Sea Lemon are similar, but are a little less common. One of the primary identifiers is that the brown spots extend up onto the tubercles and the gills have yellow rather than white branchial plumage.