| Dictionary, Encyclopedia and Thesaurus - The Free Dictionary 3,917,566,916 visitors served. |
Dictionary/ thesaurus | Medical dictionary | Legal dictionary | Financial dictionary | Acronyms | Idioms | Encyclopedia | Wikipedia encyclopedia | ? |
Merostomata |
Also found in: Dictionary/thesaurus, Wikipedia | 0.01 sec. |
|
|
Merostomata [‚mer·ə′stō·mə·də]
(invertebrate zoology) A class of primitive arthropods of the subphylum Chelicerata distinguished by their aquatic mode of life and the possession of abdominal appendages which bear respiratory organs; only three living species are known. Merostomata a class of predominantly fossil marine arthropods, related to the trilobites and arachnids. (Merostomata are joined with the arachnids in the subphylum Chelicerata.) Respiration is by branchial gills. The body is covered with a chitinous carapace and is divided into a cephalothorax and a spiculate abdomen, each bearing six pairs of appendages (the abdominal ones have branchial plates). There are three or four orders. Two or three orders are traced to the Cambrian and Devonian, while one—Xiphosura—appeared in the Silurian and exists now. The extinct order Eurypterida is often assigned to Merostomata. Want to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit the webmaster's page for free fun content. |
|
| Encyclopedia |
| Free Tools: |
For surfers:
Free toolbar & extensions |
Word of the Day |
Help
For webmasters: Free content | Linking | Lookup box | Double-click lookup |
|---|