Arbustal Snails

I've been finding these small snails up in the shrubs (and bushes and perennials and succulents) since mid-winter. When seen during the day (when I am awake) they are in their resting or protective posture well up in the plants, maybe on the underside but by no means always; sometimes right out in the open sunlight. When it was raining I happened to notice they had their heads and foots out crawling around on the plants. Unfortunately I didn't have my camera at hand as I was walking briskly to the car between drops (as you know, southern californian humans will melt to nothing if too much rain falls on us).

These snails have been seen on aloe, agastache, senecio, and on milkweed. It's weird seeing snails on these plants, the soft-bodied animals among the thorns of aloe, on the dried-up hyssop flowers, on the toxic milkweed. I do not think these are cantareus aspersus, brown garden snail. The shell doesn't look quite the same; they don't act the same although of course c. aspersus commonly climbs walls and trees; I haven't seen any bigger than 1/3" shell diameter; I'd like to imagine this is an outbranching in mollusk diversity in the garden. However, I'll be darned if I can find info on another likely species of garden-dwelling snail around these parts.