Note: This historical image is not a factually accurate paleontological restoration.
Reason: Oudated reconstruction of great appendage (multichelate in Alalcomenaeus) and number of trunk segment (11 instead of 12 in Alalcomenaeus).
You may ask further questions about the accuracy of this image at the image review page of Wikiproject Palaeontology on the English Wikipedia. Note that this image may be appropriate to illustrate obsolete paleontological views.