Not a Canadian species, Parmarion martinsi Simroth, 1893 is an invasive semi-slug in Hawaii. I photographed these individuals in January on the undersides of woody debris at Puu Kukae (a cinder-cone hill) in Puna District, Hawaii Co., Hawaii.
This semi-slug (that is, midway in body form between a slug and a snail) is likely native to Southeast Asia, according to a paper that I found on the internet (Hollingsworth et al. 2007). First noticed on Oahu in 1996, it was found the Puna District in 2005. Apparently it is also in Kailua-Kona.
Parmarion martinsi is also a vector for Rat Lung Worm (more here).
- Hollingsworth, R.G., R. Kaneta, J.J. Sullivan, H.S. Bishop, Y. Qvarnstrom, A.J. da Silva & D.G. Robinson. Distribution of Parmarion cf. martensi (Pulmonata: Helicarionidae), a new semi-slug pest on Hawai‘i island, and Its potential as a vector for human Angiostrongyliasis. 2007. Pacific Science 61(4): 457–467.