Page:The Eurypterida of New York Volume 1.pdf/258

 a fairly continuous series of later growth stages, the first two of which correspond in size to Claypole's, the last two to his. In the introductory remarks we have already given reasons for uniting the two names. These can be briefly restated as consisting in the absence of the distinguishing characters cited by Claypole and in the agreement of the dimensional proportions in the smaller and larger individuals. There appear to exist a few actual differences between the smallest and

largest specimens, which can be more plausibly explained as growth differences rather than varietal distinctions. There are the somewhat greater width of the carapace and more convex lateral margin, the greater thickness of the walking legs and swimming legs in the largest specimen, all of which combine to give the latter a more robust and less agile appearance. The same age difference we have observed in other eurypterids, as has been noted more fully in another place.