"Head about 8 cm. long; when flattened 9 cm. broad across parietal foramen; squamosal and temporal bones projecting backwards in points much behind the condyles; parietal foramen small, orbits large; length of longest tooth seen 7 mm.; cranial bones closely and deeply pitted; humerus with very thin bony walls, cartilaginous within, 3.5 cm. long."
Erect tree, coal formation, at the South Joggins; collected by P. W. McNaughton. Type in Peter Redpath Museum at McGill University. Dawson regarded the form as of uncertain relationship.
[CHAPTER XXV.]
THE STEREOSPONDYLOUS AMPHIBIA FROM THE COAL MEASURES OF NORTH AMERICA.
DEFINITION OF THE ORDER STEREOSPONDYLIA ZITTEL, 1887.
Zittel, Handbuch der Paleontologie, Bd. III, Abth. 1, p. 397, 1887.
Large terrestrial vertebrates; largest of the class. Skull equal to one-fourth or one-third of the entire body in at least one species, Metoposaurus diagnosticus von Meyer ([242]). Lateral-line canals always present ([458]) on the skulls as deeply impressed grooves which, in life, were possibly roofed-over by a cartilaginous or other connective-tissue membrane. The sensory organs undoubtedly being supplied by the superficial ophthalmic branch of the trigeminal nerve, branches of which pierced the cranial elements near the grooves, no evidence of such openings in the bottoms of the grooves; the condition probably being analogous to Hydrolagus colei and other chimæroids. Vertebræ stereospondylous, with well-developed neural arches from which projected the well-developed zygapophyses, sometimes slightly amphicœlous and pierced for the notochord, such forms being uncertainly placed in the group. Tail unknown, possibly short. Limbs and girdles well developed ([243]), phalangeal formula unknown; carpus osseous and tarsus unknown. Pectoral girdle composed of osseous scapulæ, clavicles, interclavicle, coracoid (?); clavicles and interclavicle ventrally sculptured. Pelvic girdle composed of osseous pubis, ischium, and ilium ([242]), the pubis a small plate, in life largely cartilaginous, the three uniting by cartilaginous union to form the acetabulum. Ventral armature unknown, possibly wanting.
Range: Pennsylvanian to Upper Triassic.