About Phidiana hiltoni (O'Donoghue, 1927)
This species of nudibranch, Phidiana hiltoni, grows up to 50 millimeters, which equals a little more than 2 inches in length. A reddish or brownish line across its head is almost always present, and this marking is a very characteristic feature of the species. Phidiana hiltoni can be mistaken for Hermissenda crassicornis, a species that looks superficially similar to it. Phidiana hiltoni has a rather limited distribution range. It occurs from the central California coast to Baja California, Mexico, and is also found in the Gulf of Mexico. Recently, its range has extended northward, and the species is now found north of San Francisco Bay.
