A huge, filter-feeding Tetragnathia inhabiting the open ocean of Horus.
«While specimens of giant jetwhales (Propellocetus sp.) were often found as rotting carcsses or skeletons heaped on the beaches of Bastet, and recobstructed with reasonable accuracy by comparing them to their smaller coastal relatives, the moment of their true discovery is among the most memorable in all the human history on Horus. I was returning to the Greyhound on a launch loaded with jars of silt in a particularly deep part of the Sea of Memphis, when the oarsman noticed an anomalous rippling of the water surface. The sailors a hundrd yards away started shouting us to go away, as a huge shadow was taking form right under us. Immediately after that, the surface of the sea exploded, and a colossal shape leapt thirty feet in the air in an eruption of froth, before falling again in the water. That was, of course, the gargantuan jetwhale (Propellocetus magnificens), the largest and heaviest animal known to us on Horus. Despite being longer than our blue whale, up to 45 m (135 ft), it's actually less heavy, as a large part of its volume is taken by a hollow tube. This tube, homologous to the propelling tube of the torpedo gutfish and present in all he Parachordatan early embryos, allows the jetwhale to swallow a huge amount of water, which is then pumped backwards by peristaltic motion and forcefully expelled by a posterior nozzle. The motion of water has a threefold function: it carries water through filters which retain the organic particulate, it brings new oxygen to the great lung of the creature and it provides a mean of locomotion by reaction, analogous to that employed by cephalopods and jellyfish on a much larger scale. This means that the jetwhales always move at pulses, swallowing new water in each pulse to be used for the next. The Willermann's organs, basins covered in receptors located at the base of the large palp jaws, unique to this order of creatures, are extremely sensitive to the chemical nature of the water, and allow jetwhales to choose infallibly the most nourishing volume. The ancestral four-fold symmetry is still obvious in Propelloceta even more than in other Tetragnathia, particularly in the disposition of eyes, palp jaws and Willermann's organs, with a few exceptions, such as the fins and the cerci, and most remarkably the digestive tract, which branches in the throat from the propelling tube and is wrapped as a helix around it, only to reconnect in the nozzle, where waste is expelled along with water.»