Acorn Worm

The acorn worms look like elongated worms with an acorn like head. The "acorn" is made up of a proboscis, or tubular structure, and a collar, into which the proboscis fits. The collar is attached to a long, flat, ruffled trunk, tapering toward the end. The animal ranges in length from an inch to four feet ; the average length is from six to ten inches. These relatively rare creatures are found on the Atlantic coast, buried in the mud and sand of the low tide zones. Like in the same way as in the vertebrates and is made up of the same tissue. Other authorities deny that the acorn worm has a chordate. They include the animal with the invertebrates, because it resembles them in many respects. The acorn worm's pharynx leads into the intestine, which is perforated with gill slits. The gills lead into a pouch, which opens to the exterior by gill pores. The intestine runs the length of the body. It ends in an anus at the tapered end of the trunk. The reproductive organs are located at the front end of the trunk. The sexes are separate; males produce sperm and females eggs. Fertilization takes place outside of the body after the sperm and eggs have been ejected from it. Some deep sea types, such as Hydrocephalus, reproduce asexually by budding. The larvae of acorn worms resemble those of the echinoderms (sea stars, sea urchins and their kin) in both structure and development. For this reason many believe that the chordates are descended from the same stock as the echinoderms. 
             

 shallow sea water one often finds orange, red or purple bearlike objects attached to rocks, piles and seaweed. These colorful "bags" are the primitive chordates In the adult animal, water bearing food particles passes through the mouth and is  filtered through gill slits. Food particles are trapped by the gill slits and enter the intestine. The water then flows into a surrounding sac  the atrium  and out through the siphon called the atrial pore. Undigested waste materials also pass out of the body by way of the atrial pore. Communicates can reproduce by budding. An adult buds again and again, producing new individuals. In time a large colony may develop on a rocky surface. Sexual reproduction also occurs. Communicates are hermaphrodites: that is, each animal produces male and female sex cells sperm and eggs. Fertilization may take place within the body ; or eggs and sperm may pass out of the body and unite elsewhere.