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 E. newlini, the last two to his E. ingens. 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

TABLE OF MEASUREMENTS OF EUSARCUS NEWLINI

Parentheses imply approximate measurements.

¹ Claypole records E. newlini as measuring 10–12 inches. The original drawing measures 5¼ inches and can therefore be safely considered as being a one half reduction.
² The legs are measured to median line of carapace. Measurements too small from figures since full length of spines not drawn.
³ Drawing obviously not reliable an to this proportion.
⁴ Claypole gives as the length of the type 24 inches, but from the scale appended to the original drawing the original would measure considerably less. The drawing measures 6½ inches. We assume therefore that it is reduced to one fourth and that the scale is incorrectly drawn.

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.