I've seen a few other trade cards with seashell illustrations, but passed them up because they were, well, ugly. The salesman sample card above tells us that it is #90 (90!) in the series Gems of the Seaside, and has an 1877 copyright. I've cleaned them up, brightened the colors, and included versions without the trade information.
~That Sapanule must have been some kind of miracle drug.~