When it's a shrimp, however, things get confusing. The "walking legs" include the chelipeds, or pincers (two sets), which are right next to the maxillipeds, which Wikipedia counts among the five, but which would make up six on the shrimp. They also count as mouthparts. Then there are the 5 pairs of swimmerets; in diagrams, they look like legs. Luckily, in real life they're small, and mostly hidden under the tail segments.
I've been trying to count the legs on the largest of my shrimp, now that he's got a bit of colour. It's difficult. Maybe if he would just stop moving for a moment ...
|Counting from the rear; 1 2 3 4 ... Aaargh!|
Some things are easy; he has two sets of antennae, one long and one short. The long ones are very fine, transparent, always flicking about, and maybe twice his length. Can you see them here?
|Photo cropped at tips of antennae.|
|5 legs countable. And with the chin up, separated from all those sharps on the head.|
|Let's name them.|
|Diagram from Louisiana Fisheries|
So we've got 5 walking legs, the front two of which are also chelipeds, because they have pincers on the tips. Small ones, only visible in a few photos. If you look closely at the centre of the first clump of feet on the photo above, you can see one in the background.
Then there are the maxillipeds, which would correspond to our jaws (Maxilla): they would be the two straight blades sticking forward at the mouth.
Along the top, toothed like a saw blade, sharp as a spear, is the rostrum. On either side of it are the two stalked eyes (another set of appendages), and the shorter antennae. (So far, so good.)
But then, what are the two flags he waves above his head? And what do they do?
|Top view. Look at it full size (left click - open new tab) to see the various tools he's carrying.|
The little shrimp, half the black one's size, are just beginning to show their stripes, and pick up a bit of colour. They wave tiny flags, too.
|1/2 inch long shrimp. His innards are easier to see than his head accroutements.|