Unidentified Slug

In addition to the Leopard Slug, we also have this slug in the Colvin Run Habitat.

I do not know what kind of slug it is...a banana slug??? Since someone identified the spider, I am hoping someone will identify this slug. Anyone???

This slug was moving around the nylon grill cover. In the first two photos, you can clearly see the slim trail left.

These photos were taken last summer.