Page:The Eurypterida of New York Volume 1.pdf/214

 convex, antelateral angles well rounded, lateral margins nearly parallel, slightly concave in the middle and curving outward toward the genal angles which are slightly produced sideways; posterior margin nearly straight transversely; eye nodes subcircular, small (about one seventh the length of the carapace), situated just forward of the center and twice their diameter from the lateral margin; the form and size of the visual surface have not been made out.

The surface of the type specimen exhibits, especially on the posterior portion, low, rather broad nodes, so closely arranged as to be in contact at their bases. A body segment lying close to the carapace possesses a similar ornamentation.

Patches of integument are found associated with the eurypterids at Schenectady which present the aspect of a shagreen, their surface being covered with low, flat nodes which in many places become so crowded that they assume polygonal outlines. We consider it probable that these patches belong to this species.

Horizon and locality. Frankfort shale. Dettbarn quarry, Schenectady, N. Y.

Description. Body of small size, very plump in general appearance, the carapace and preabdomen forming a broad oval from which the postabdomen is set off rather abruptly.

The carapace is strikingly broad (length : width as 5 : 7) and nearly as wide as the broad preabdomen; subrectangular in outline; anterior margin straight to slightly emarginate in the middle and rounded at the anterior corners; lateral margins gently convex, slightly contracted toward the posterior angles; its doublure remarkably broad, forming a wide rim (4 mm) that gradually narrows along the sides; it bears a deep broad furrow in the middle that ends somewhat abruptly just behind the anterior corner, and fine parallel striae on the flat portion outside of the furrow; along the inner edge of the furrow runs a narrow crest. The rim seems to have been