from Wiktionary, Creative Commons Attribution/Share-Alike License.
- proper noun A taxonomic
orderwithin the class Merostomata— distinguished from all other cheliceratesby having compound eyes. The only living xiphosuransare the horseshoe crabs.
from Wiktionary, Creative Commons Attribution/Share-Alike License
This extraordinary crustacean is one of the oldest of living animals in its history, as it is closely related to the Xiphosura and even the Trilobites of the Primary Epoch, which existed millions of years ago.
Crustacea; nor the Xiphosura and Trilobites, because, having never investigated them myself, I knew too little about them, and especially because I am unacquainted with the details of the explanations given by
Phyllopoda and Xiphosura, furnished a long and varied, and at the same time intimately connected series, such as was at my command in no other class.