Saw about a dozen of these washed up on Mad River Beach in Humboldt County, California today. Sizes were 150 to 250 CM. None had shells attached. My best guess based on Wrobel and Mills is Carinaria japonica. Have only seen one other in 20+ of looking for stuff like this.
From last week
Large moth the size of a small bat flew through parking lot and landed in tree.
eating trash along the side of the road