Page:The Eurypterida of New York Volume 1.pdf/34

 represented the carapace of Eurypterus as evenly rounded with the exception of the frontal elevated areas.

The usual waterlime material does not give any evidence of the original form of the carapace of Eurypterus, the integument having been completely flattened out in the fine mud. A sandy dolomite bed of the Bertie waterlime at Morganville, Genesee co., has however furnished a few specimens of  that are uncompressed. These [ pl. 6, fig. 6] have glabellalike posterior median ridges well defined by two subparallel furrows deepest half way between the posterior



margin and the ocellar tubercle, which, by the way, the glabella does not quite reach. They also show a crest extending from the lateral eyes to the posterior margin and separating the elevated apical area from the steeply outward sloping lateral areas. This sculpturing is so remarkably like that of Limulus that we have no doubt it represents a general feature of the eurypterids. The dorsal furrows bounding the glabella correspond to entapophyses, serving for the attachment of muscles. The appended sections of Limulus [text fig. 5, 6] show the relation of the glabella to the position and extension of the heart and the relation of the glabellar furrows to the muscles holding in place an internal cartilaginous