desegmentation

Century Dictionary and Cyclopedia

1. n. The process or result of uniting several segments of the body in one; the concrescence of several originally distinct metameric segments into one composite segment; the state or quality of not-being segmented. Thus, the thorax of an insect, or the carapace of a lobster, or the cranium of a vertebrate, is a desegmentation of several segments.

Wiktionary

1. n. anatomy The loss or obliteration of division into segments.

GNU Webster's 1913

1. n. (Anat.) The loss or obliteration of division into segments.