Unlike vertebrates, this category is more of an "everything else" category than a closely related group of organisms.  For example a Lobster and Sponge are both invertebrates, but I think most people can see that they aren't as closely related as say a chicken and a cow.  If you don't believe me imagine trying to scrub your dishes with a lobster, or serving sponge for dinner.  On the same note I could order Chinese right now and bring home chickens, lobsters and cows.....

In order to minimize the number of pages you have to click through, groups will be added to the menu below based on "popularity" and the number of specimens rather than strict Phylogeny.