The Anatomy of Xers and Towers

The first primitive xers appear to have been very small, just a mouth with four legs and possibly with light-sensitive eye spots. Their mouths were underneath their bodies, at the center of the x made by their legs, and the little animals would position themselves over small plants and digest the plant material and any little animals that were on it. There are still small, flat xers in Shalimar's seas that measure less than an inch across: we believe that the first xers were very much like these tiny examples.

Xers have diversified into a number of species. Some have remained fairly flat, and continued to crawl slowly over the rocks, eating whatever they could find. Others have grown taller, increasing the height of their bodies and the space inside themselves for digesting their food. Xers now vary considerably in size, some being almost 30 inches tall. As they have evolved, their bodies have become more complex.

Xers do not have bones. Their four legs are muscular and flexible, and have suction disks on the undersides. Their bodies are x-shaped when viewed from above, and have two eyes on each side, making a total of eight eyes in all. The eyes are near the tops of their bodies. Long flaps of skin join the sides of their bodies near the center of the x, making four tubes. Water flows through these tubes, bringing oxygen to the blood circulating close to the skin in these areas. Numerous delicate and rather tender velvety cells inside these tubes absorb oxygen from the water.

Looking at an zeroes body from above, we see the tubes between the arms (in yellow) through which water flows to oxygenate the blood. We see that there are powerful muscles inside the arms that shorten the arm and pull the arm and the body closer together. Muscles on the outside of the arms lengthen the arms and make them seem thinner. Major blood vessels flow between the two sets of muscles to nourish them. The mouth is in the center of the body.

When we look at the xer's body from the side we see that in some of the more advanced species the body is elongated and the stomach cavity is quite large. Above the stomach there is space for the brain. At some point in the xers' evolution the xers began to store gas in small spherical spaces in the tops of their bodies: apparently this helped to keep the body upright in the water by making it buoyant. As the nervous system became more complex, some of the spaces filled by gas were taken over by nervous tissue, so the xers' brains are physically a network of nodules. (We have no idea of what effect this might have on their mental processes.) Large nerves run down the body and spread out into smaller nerves in the arms and around the mouth. Although the skin of the body is tough and thick, it is also well supplied with sensory nerves, especially over the breathing areas.

We see that the body is also ringed with muscle. As there are no bones in the body, the muscles can cause the body to change shape. The nodular nature of the brain seems well adapted to distortion stresses, and the remaining gas nodules in the brain area seem to protect the nervous system, cushioning it like the bubble plastic that humans use for packing delicate items.

Over the course of evolution, xers have come to fill a number of niches. Small xers continue to thrive on the bottom of the seas. Larger xers became predators in water, eating various kinds of worms and also the triangularians. These xers move fairly quickly as they clamber over the rocks. Their buoyant upper bodies sway gently in the currents. They appear to be intelligent, and are alert to the threat offered by the ravenous triangularians. They have learned to use the tips of their arms for picking things up, while using the part closer to their bodies to function as stumpy little legs.

A few. like the one below, have used their buoyancy to actually become free swimming.

These floating xers also appear to have become intelligent. They float a little below the surface of the water because they have air chambers at the tops of their bodies. They can guide themselves with their widened, paddle-like arms, but are not strong swimmers. They need to stay in calm waters, away from storms. They have learned to put food into their mouths with their arms. They are graceful creatures.

© Elizabeth Anne Viau, 1996. This material may be used freely for instructional purposes but not sold for a price beyond the cost of reproduction. Please e-mail me at if you use this material. I'd be interested to know how it works for you!