As the class of fishes is the most lowly organised and appeared before the others, we may conclude that all the members of the vertebrate kingdom are derived from some fish-like animal, less highly organised than any as yet found in the lowest known formations.

Please remove spaces between words.
Astheclassoffishesisthemostlowlyorganisedandappearedbeforetheothers,wemayconcludethatallthemembersofthevertebratekingdomarederivedfromsomefish-likeanimal,lesshighlyorganisedthananyasyetfoundinthelowestknownformations.