 All right, Dog Pounds. Now, we're going to do a couple of different things here. First of all, everything beyond this point is going to be bilateral. It's going to demonstrate bilateral symmetry. Bilateral symmetry. Now, tell me, jellyfish, sea anemones, what kind of symmetry do they demonstrate? Radial symmetry. So we can, now sponges demonstrate no symmetry in their bodies, but everything from here on out is going to be bilaterally symmetrical. And we're going to do something a little bit wonky with our cladogram. And the reason we're going to do this, it's not entirely accurate, but I think the cladograms become kind of overwhelming to my cute little students and I don't want to overwhelm you. So what I'm going to do is our characteristic that we're going to look at for defining the next three groups is protostomy, protostomy. So everybody that we're going to talk about, the next three groups we're going to talk about here, their blastopores became their mouths. And we're going to go ahead and do something that, again, we don't do. And the reason why I'm doing this is not because we don't know this, but I'm just doing it because it just gets too complicated. And we don't need these kinds of details. What I want you to know is that everything else is a protostome and we're going to deal with a group called the worm group. And I just made this up and I'm bunching a whole bunch of different worms into this group. They're not really like the same thing. We're also going to look at the mollusks and we're going to do that in a different section and we're going to look at the arthropods and they're all protostomes. And I'm not going to talk about how they're related to each other because there's things that, like we'd have to break it down even further and we're just not going to do that. You probably have a decent idea but if we're going to break off the protostomes, then we're also going to have a group of deuterostomes and we will deal with those guys last. So let's talk first about our little worm group. The worm group is going to include the phylum platyhelminthes and this group actually is, there's a lot of questions when it comes to platyhelminthes, like how these things are actually related to each other. I don't know but that little guy is cuter than all get out. You can actually find them if you go to a river and look under a rock, you'll see. You can find little platyhelminthes flatworms and my kids are super obsessed with these things. In fact, we had some for pets. I'm not sure how we end. I feel like maybe they got them for zoology and they were feeding them and observing their behaviors. I think that's what it was and then they were just going to like piece out to the platyhelminthes and so I snagged a couple and took them home to my kids. My kids really wanted to do the experiment where you cut them in half. You can do a, like a, what would this be? Like a section, like cut them long ways down the middle. And sad story that they'll actually grow their parts back. My kids couldn't bear to have my kids donning razor blades and chopping worms in half. So we didn't actually do the experiment but these are pretty cool critters. This group also includes, dude, I think this is the group that includes tapeworms and liver flukes. So let's talk tapeworms. I've got a jar of horse tapeworm, one tapeworm that came from one horse and it's a jar this big. It looks like it's a whole bunch of egg noodles in there but those are tapeworms, man. Parasites are so cool. Tapeworms just chill in your guts and like eat your food. Here's another group of worms. These worms are super familiar to you because analysts are segmented worms and they include earthworms. They also include leeches and they also include these polykeet worms that are ocean segmented like bristly worms. Those guys are kind of cool, a little creepy when you run into them at the beach. We're not going to talk about mollusks yet. Were there any other worms I wanted to talk about? I mean, surely there's something else, nematodes. Dude, nematodes are amazing. There's a worm called a nematode that you dissect in zoology and it actually is a parasite that if you get its eggs inside of you, the eggs will grow and do their thing and then it crawls up the back of your throat because it was in your stomach and out your nose because it wants to get out and go lay eggs somewhere else. So when you dissect that parasite in zoology and be sure to wash your hands afterwards. Yeah, okay, that's cool. Let's talk about another group of protostomes, mollusks.