Page:The Eurypterida of New York Volume 1.pdf/161

 To sum up the foregoing distinctive features in Strabops, we find that the lack of differentiation of the parts of the abdomen and the general primitive aspect of the form, together with the high geologic age of the genus warrant its recognition as distinct from Eurypterus, though it is manifest that the form is very similar thereto.

The genus Eurypterus embraces not only those representatives of the order Eurypterida longest known and most completely understood, but it also surpasses all other genera in the number of species and in geological and geographical range; it represents the most vigorous and the most typical genus of the order, although it does not contain the giants of the group. It is therefore very proper that it should have given its name to this remarkable order of the class Arachnida.

The genus was erected by James E. DeKay in 1825 for the most common of the New York species, viz,. The organization of the body of Eurypterus was first elucidated and elaborately described by Nieszkowski [1858] and James Hall [1859]; the former basing his observations on the finely preserved material from the island of Oesel in the bay of Riga, Russia, the other on that from the waterlimes of New York. Hall described seven supposed species from the New York rocks, viz,,  ,  ,  ,  ,  ,  , to which a few have been added since from the rocks of this State, viz,   (?)   Hall and Clarke [1888],   Sarle [1902] and   Clarke [1907]. A form from the Guelph dolomite of Canada ( Whiteaves), two from the waterlime of the same horizon at Kokomo, Indiana (  Miller & Gurley and   nov.) a small number of species from the Carbonic of Illinois and Pennsylvania (,  ,  ,  ,   and  ); and the species  ,