In Leptostraca, the appendages on the telson instead form caudal rami (spine-like protrusions). The pygidium is formed from a number of segments and the telson fused together. The abdomen ends in a telson and a pair of long, thin, multi-articulate caudal rami. The term "telson" is widely used for the caudal spine of some chelicerates . The telson includes the vesicle, containing a symmetrical pair of venom glands. They have a long spiny tail known as the telson. Despite this, there are some noticeable changes occurring in the chelicerae, telson and metastoma. There is a tiny, button-like telson at the end of the thorax. Together, the telson and uropods form a splayed tail fan. The shape and composition of the telson differs between arthropod groups. Unlike some species, there are no serrations on the telson and the spine is blunt. The anatomical part of the scorpion that delivers the sting is called a "telson". The tail bears a long spike, known as the telson. THE GOSPEL AT COLONUS (Sophocles, adapted by Breuer/Telson), Arena Theater, Washington D.C. The body is elongated and cylindrical, with a postanal telson at the end.