fourth the width and one eighth the length of the carapace; basal margin slightly concave, the postlateral angles subrectangular. 
Fig. 96, 97 Eusarcus linguatus nov. Fig. 96 Holotype. × 2. Specimen somewhat disorted. Fig. 97 Cotype. × 1.5. Younger individual showing traces of the sculpture, the frontal process and the ocellar mound Eyes marginal, circular, small, a little longer than one fifth the length of the carapace, situated in an angle between the lateral margins and the base of the frontal process. Surface densely covered with relatively large flat nodes. The type measures 9.4 mm in length and 10.5 mm in width.
This species strongly suggests the Eusarcus vaningeni, with which it has not only the peculiar anterior snout in common, but also the general outline and the position of the eyes. It is also closely related to the species here described from the Normanskill and Schenectady shales as Pterygotus? (Eusarcus) nasutus, which possesses a less prominent anterior process and more distant eyes but is very similar to this species in outline and surface ornamentation.
We also refer to this species a number of specimens which correspond to the above description in all particulars but lack the anterior process and assume that the latter may either be broken off or be folded under normally like the epistoma of Pterygotus; with present material we have no means of deciding which.
Dolichopterus breviceps nov.
See text figure 98
Fig. 98 Doli-
chopertus breviceps nov. Holotype.
× 3
A small carapace differs from the others in the position of its lateral eyes which are submarginal in the antelateral angles, thereby suggesting the presence of a species of Dolichopterus. The carapace is rather short subquadrangular, its length to its width as 5:7; the lateral margins slightly concave, diverging forward at a small angle, the frontal margin broadly
