| Like all insects, MHCs have three distinct body parts or tagmata, three pairs of legs, compound eyes, and one pair of antennae. |
| These tagmata may again be subdivided into groups preserving a more or less marked individuality. |
| In neither are the appendages, except those about the mouth, grouped in tagmata. |
| The trilobites show a beginning of tagmata, and such development would be expected if evolution were progressive. |
| The chelicerate body plan is characterized by two tagmata, the prosoma, including head structures, and the opisthosoma. |
| Chelicerates are characterized by a pair of chelate preoral appendages and a body divided into two tagmata, the prosoma and opisthosoma. |
