Nemerteans were one of the few macroscopic animals seeded. Out of the two classes of Nemertea, Enopla has become more diverse due to the versatility of their stylet. This large clade will be called Stabworms. To support their larger size they opted for hemoglobin in their blood to more efficiently carry oxygen through the body.

1. Scourge worms are small red worms that live in oceanic substrates all over the world, a few terrestrial and freshwater species exist as well. Instead of hunting, the proboscis is used to dig tunnels in search of detritus. Their red blood helps them survive better in low oxygen environments. They are a common prey item to many species and rely mainly on numbers to survive. They descend from Anoplan nemerteans, as do the Grove Nemerteans (5) therefore lacking a stylet.

2. Camoworms are stubby and often have many protrusions resembling algae and coral. They are predatory and rely on stealth to catch worms and other small animals in front of them. Most species have venomous stylets that can sometimes paralize prey larger than themselves.

3. Beard worms are much larger predatory nemerteans that mainly hunt other nemerteans. Their proboscis can shoot out at alarming speed to catch anything their body's length in front of them. Some species of Beard worms can reach several feet long and are venomous.

4. Clownworms are nemerteans with specificied diets and poisonous skin. They use colors and smells to warn predators that they are toxic. Most species aren't particularily colorful at the beginning of their evolution since most of their predators' eyes aren't advanced enough to see color but the few that are, are more likely to survive in the future as the nemertean's eyes become more complicated.

5. This descendant is very distantly related to the others, it comes from the class Anopla which possess no stylet. The grove nemerteans live in more temperate waters with more nutrients. They can filter feed with a specialized branching proboscis and gain nutrients from symbiotic algae in their skin. Most of the time these worms stay in one spot with their tails crammed in a crevice while the rest of the body is out in the current, but if a predator comes near they are capable of swimming in a similar way to Earth flatworms.

Terrestrial nemerteans are the most successful group on land currently. They descend from the marine beardworms. To adapt to land they have further developed their excretory system into organs that contain millions of flame cells. Essentially functioning as kidneys, these new organs filter wastes and toxins out of their bodies through enlarged nephridophore orifices. Most species of terrestrial beard worms are important detritivores that eat dead organic plant and animal material. Few are predatory, either consuming soil microbes or other scourge worms. Even with further advancements of the circulatory and excretory system, these worms are still vulnerable to desiccation meaning they're stuck living in dark humid environments. The larvae of this group are different from most nemerteans, they are smaller versions of adults instead of plankton.

Blip worms are stabworms that fill a pelagic, usually planktonic, niches in the ecosystem. They form a large percentage of the Alluvius zooplankton population and are a very important part of the general food chain. They are now preyed on by many macrotifers and jellyfish. Blip worms possess a more advanced circulatory and nervous system. A dorsal heart tube fuels their blood while the lateral nervous system gives them body support. They maintain a hydrodynamic oval shape with a sort of hemostatic skeleton and the two lateral nerves lined with ossified rings, functioning in a similar manner to vertebrate spines and squid gladii. Blipworms also have fin rays, made of a mixture between cartilage and chitin, attached to these bone rings.

The Moray Stabworm is a large nemertean that can grow a few meters long. It's an ambush predator that lunges at unsuspecting reef macrotifers with an armed proboscis. Like it's close cousins the blipworms, these predators have hearts and blood but lack notorings. They instead have a cartilaginous half pipe running above the dorsal hearts for support and flexibility. Evolved from extended sensory extensions on the rear, the group this species belongs to possesses external gills. Soft feathery organs filled with hemoglobin blood. For the most part, these sensitive parts are nudged in rock crevices safe from nipping animals but they're not safe from parasites. A nest of Grorgs could possibly infest a more sickly Stabworm, so a symbiosis evolved.

Derived from Blipworms, the Croissant worms are an incredibly diverse clade of shelled animals. During the nemertean's development, notorings grow external spikes which then fuse and become a shell, most comparable to the process Earth's turtles go through. Croissant worm diets vary wildly among species; Initially coming from generalist filter feeders, they will now feed on algae, animals, carcasses, detritus, and more. The mollusk-like worms inhabit all oceanic and freshwater environments on Alluvius. Some species are amphibious, slithering from tide pool to tide pool. All species of Croissant worm possess two gills within their shell as well as several bristles along their bodies used for breathing, protection, and/or sensory purposes depending on species.

Croissant worms being such a successful group even after the NeoEdiacaran extinction have naturally diversified heavily. The most abundant clade spawned from the Croissant worms are the Nemertopods, shelled animals with segmented limbs. These segments originally evolved in the antannae for ease of development, but later became more robust and used for movement. This was the beginning of the Nemertopod clade, which spawned many subclades. Mainly the Arthroteans and Loboteans, distinguished by calcified leg segments and soft hydrostatic limbs.

Loboteans are the sister group to the Arthroteans. They possess soft segmented legs and therefore less protection than their calcified counterparts. Many Lobotean groups have thus evolved in many interesting ways to protect and feed themselves. Most have more complex camera lens eyes comparable to basic vertebrates or arachnids. Many also contain pigment changing cells for a variety of purposes. Lobotean clades listed from left to right:

• Hypnopods - Loboteans with chromatophores on flattened limbs used for communication, hypnosis, and defense. Hypnopods typically live in burrows or crawl on reefs, using bright colors to fool predators into thinking they're poisonous. Most species use their front four limbs for hypnosis, drawing in benthic invertebrates or motifers closer so the hunter can impale them with the proboscis. Some species have interesting social interactions, fighting with dazzling colors and patterns to confuse their rivals or attract mates. Due to their color changing abilities, Hypnopods have advanced eyes that can see more colors than Humans, but not as many as Mantis Shrimp. Hypnopods will also sometimes practice parental care, storing the eggs in their burrows until they hatch.

• Onychoteans - Typically long-bodied cold water dwellers that are carnivorous. The Onychoteans possess a tail segment that grows more legs as the animal grows, starting as antennae and ending as fully functional hydrostatic Lobotean limbs. Their length aids quick movement, squeezing through crevices, and camouflage. Many will be disguised as algae and hunt Blipworms and Snatchids in a similar way to Earth Chameleons. Some are also tide pool dwellers, using their many legs to crawl from tide pool to tide pool.

• Nemertigents - Crafty reef dwelling predators with a complex brain. Nemertigents are among the ranks of most intelligent creatures on Alluvius along with the Whoppifers. Their three dimensional environments and hard to penetrate prey require their nervous system to be more complex. As well as the fact that they have less protection due to the reduced shell for further flexibility. Some use large Croissant worm or Clampifer shells as mobile homes like Hermit Crabs or Coconut Octopuses. Others can change colors over the course of minutes to blend with surrounding rock or convey mood to others. Most Nemertigents are solitary but live long and have few young. They fill niches most comparable to anglerfish, octopuses, and predatory crustaceans.

Scootaceans are a terrestrial group of Nemaceans that sift though leaf litter and logs on forest floors. During the day they bury themselves in mud not only to keep their gill chamber humid but to also to absorb minerals from the soil for shell growth. Like Earth mollusks, their hard parts are made of calcium carbonate which is far less common on land than in the ocean. These creatures serve as important ecological garbage disposals and as food for many Ogreworms, Cobraworms, Inchifers, and Terrifers. Unfortunately the Scootaceans shell limitations and gills will never allow it to reach the diversity of insects or the size of tetrapods but they fill an important role in the environment none the less. Scootaceans are also canonically adorable.

Tracheavermi moved into brackish and freshwater habitats relatively quickly after their radiation, though only the Tentacular clade made the jump. Most fill niches analogous to large freshwater Earth fish like Pikes, Arapaima, Gar, and Catfish. Most are venomous and are able to paralyze prey though some have a shorter rhynocoel and proboscis in exchange for longer grasping tentacles. All species are carnivorous hunters of Rochovies, Eelifers, and small Sarcoptifers. Freshwater Tracheavermi have more highly developed trachea as well, especially ones that live in murky or still waters.

Tetraverms are a result of their prey, the Lurkifers, becoming terrestrial. Some Tetraverms compete with the Lurkifers while most others consume them. Tetraverms are typically ambush and chasing predators of Rochovies, Eelifers, Inchifers, Terrifers, and Swampifers. Unlike their contemporaries, Tetraverms have permeable skin, vulnerable to dryer terrestrial environments. This limits all Tetraverms to wet rain forest environments. Despite this they have several advantages. These large Blipworm descendants have trachea capable of breathing air and water as long as they're wet, and two pairs of enlarged fin rays for crawling. Tetraverms spend most of their time in water like Swampifers but some species will travel several meters inland in search of prey. All species have a gizzard and swallow stones to break down food. Tetraverms all have seven limb bones stemming from their vertebrae while their aquatic relatives, tracheaverms, can have any where from seven to thirty depending on size of fins.