- zoology the posterior part of an arachnid's abdomen (opisthosoma) that never carries appendages
Examples from the Web for metasoma
It is probable that we have in the metasoma of Limulus a case of the disappearance of once clearly demarcated somites.
There is nothing among the trilobites comparable to the movable lateral spines of the metasoma of Limulus.The Appendages, Anatomy, and Relationships of Trilobites
Percy Edward Raymond