There are now a number of newly described species that used to fall under the umbrella category of “Yellow-edged Cadlina” or Cadlina luteomarginata.  Recent research has identified several new species: Cadlina klasmalmbergi, Cadlina sylviaearleae and Cadlina jannanicolsae. The most notable difference between the C. luteomarginata, C. klasmalmbergi, C. sylviaearleae is that the latter two have smaller tubercles and have yellow or white spots near the mantle edge.  Telling the two apart by photographs alone is pretty much impossible, so I have included images and suggested both possibilities until more research enables a confirmation of identification.  Karin Fletcher has suggested that the Pacific Northwest likely has more C. klamalmbergi than C. sylviaearleae but that too is to be determined.