nected in the same specimen, our larger collection of individuals in various growth stages and states of preservation leaves no doubt that the types of both belong to one species, which must be named P. macrophthalmus, as the latter precedes the other in the original descriptions and is better characterized by being based on a carapace. Professor Whitfield's accurate drawings show all essential features of the type specimens of P. macrophthalmus. We may add that Hall's figure 6, plate 80A, which is described as "a fragment of a crustacean associated with the E. remipes at Waterville, the relations of which have not been determined" is the broken fixed ramus of the pincers from a young individual of P. macrophthalmus.
Pterygotus macrophthalmus is quite distinct in its characters from all the European species. It is closely related to P. anglicus, in the similar form of the telson, but it is readily distinguished from the British type by characters of its own. One of these is the fishhooklike form of the extremities of the chelae and the different direction of their teeth. These features, at least the form of the distal ends of the chelae, are approached by P. osiliensis, a species with widely different telson.
Pterygotus atlanticus nov.
Plate 79, figures 3–5
Pterygotus sp. Whiteaves. Canadian Naturalist. 1883. 10:100
Remains of Pterygotus recorded from several Devonic horizons of eastern Canada have been briefly referred to on a previous page.
Billings, in Logan's Geology of Canada, cited their occurrence at Cape Bon Ami, Gaspé; the single specimen, however, proves to be not from the Bon Ami beds, but from the higher or Grande Grève limestone of the Lower Devonic. This specimen is a fragment of two abdominal segments, together having a length of 75 mm and covered with closely crowded, very coarse scales curved into the arc of a circle. It indicates a species of rather commanding dimensions. Sir William Logan also reported the
