telson

1. (zoology) The part of an arthropod or crustacean posterior to the last segment, often resembling an armored tail or tip of the tail.Examples: "Although Crangonya evidently comes very close to Niphargus, it appears to be a good genus, and to differ constantly from Niphargus in the more robust body and in the telson, which is always entire and never cleft as in Niphargus."; "The basic number of segments in the abdomen is eleven plus the postsegmental telson which bears the anus, although Matsuda (1976) regards the telson as a twelfth segment."; "The two documented examples of telson abnormalities are on juvenile moults (Fig. 2a, b)."