Erik Norman Kjellesvig-Waering

“ The largest carapace (H-6) has eyes that are 6.8 mm. in length and 4.5 mm. in width.
Although the details of the Type B operculum are known (Kjellesvig-Waering, 1948, p. 23, pl. 1, fig. 6) , those of Type A are mainly known from an inconclusive outline given by Meek and Worthen (1868a, pp. 19–22) , as the holotype is a dorsal impression and the shape of the operculum could only be surmised by its reflection through the mesosoma. ”

“ An examination of the ratios of both length/width-at-base and length/width-behind-eyes reveals that A. mansfieldi progressively becomes more narrow in the carapace with age as compared to A. mazonensis, whose ratios remain constant.
Van Oyen (1956, p. 38) states that his conclusions regarding the measurements of the eurypterids from the "Veine D" are based on the measurements of 130 carapaces. ”

“ Other American species, such as Adelophthalmus (?) potens (Hall) , he also lumps together under the Bohemian A. imhofi, although the former probably does not represent the same genus or even the same family as the Bohemian form. Considerable evidence indicates that A.? potens (Hall) should be referred to the Hibbertopteridae.
Of the "Veine D" eurypterid carapaces figured and measured by Van Oyen (1956) the following are considered sufficiently well-preserved and complete to use for biometric studies:
1 Not measured although complete and mainly undistorted. ”

“ The only known, well-preserved, and entire male (Type A) mesial appendage of Adelophthalmus. This occurs in a specimen of A. mansfieldi (C. E. Hall) from the Pennsylvanian, Allegheny group at Cannelton, Darlington township, Beaver County, Pennsylvania; previously figured by James Hall (1884) . In Adelophthalmus mansfieldi and A. mazonensis the length/width-at-base (of the carapace) ratios and the length/width-behind-eyes ratios show little difference when plotted and when not taking into consideration the important preservational factor. ”

“ The specimen with the alimentary canal preserved is in the private collection of Francis Tully, of Lockport, Illinois; the copper cast, PE 6174, is in the collection of Chicago Natural History Museum.
Remarks.—The mode of preservation of eurypterids, particularly with reference to biometric studies, is of primary importance. It should be emphasized that the more incompetent the encasing material, the greater the amount of distortion that is found. ”

“ The longest-living author of this work died in 1979, so this work is in the public domain in countries and areas where the copyright term is the author's life plus 43 years or less. This work may be in the public domain in countries and areas with longer native copyright terms that apply the rule of the shorter term to foreign works. ”