British Columbia to California
Howe Sound, British Columbia, Canada. 35 feet, approx 1 cm long. Photo: Marli Wakeling.
Closely resembles, and previously mistaken for, Onchidoris muricata. It grows to 15mm but is usually about 7mm long. The notum has numerous stalked spiculate tubercles. They are rounded but sometimes slightly pointed. They are pale yellow or creamy white in the north of their range(Canada) and orange or lemon yellow in California. The brownish digestive gland and creamy gonad can be seen through the semi transparent mantle wall. In Canada it is often found on the blades of laminarian algae which are colonised by bryozoans of the genus Membranipora. However in California, orange coloured specimens have been reported feeding on the orange coloured bryozoan Lyrula hippocrepis intertidally, and yellow ones on Reginella mucronata.
• Millen, S.V. (1987) The nudibranch genus Adalaria, with a description of a new species from the northeastern Pacific. Canadian Journal of Zoology, 65: 2696-2702.
Rudman, W.B., 2001 (February 25) Adalaria jannae Millen, 1987. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/adaljann