The Dirona albolineata has numerous common names, all of which make complete sense: Alabaster Nudibranch, Frosted Nudibranch, White-lined Dirona, Chalk-lined Dirona.  All of the ones I have seen are either white or a yellowish-orange colour, but they do come in a lovely lilac/purple, lined in white. If you find a dirona of a dark orange colour with white spots, you have likely come across the Golden Dirona  This “frosted “nudibranch is particularly beautiful.  Even though it can be fairly plentiful in the intertidal zones I inhabit, it always makes for a stunning photographic subject. They tend to drop their cerata if disturbed or threatened and a few of these photos illustrate individuals who appear to have had a recent struggle.  To 180 mm or  7 inches, but most of the individuals documented below were between 2.5 and 10 cm (1 to 4 inches).