. The Cyathaspididae; a family of Silurian and Devonian jawless vertebrates. Cyathaspididae. 432 FIELDIANA: GEOLOGY, VOLUME 13. Fig. 151. Anglaspis expatriata (X 2). A, rubber impression of type, inner side of dorsal shield, National Museum of Canada 10038; B, ventral shield and part of dorsal shield, inner sides, CNHM, PF 3666. ds, dorsal shield; ^, impressions of gill pouches; pfo, impression of fossa for pineal organ; sec, impressions of semicircular canals; vs, ventral shield. Referred specimens.—CNHM, PF 3665, a flattened dorsal shield and scales, in counterpart; PF 3666 (fig. 151,B),
. The Cyathaspididae; a family of Silurian and Devonian jawless vertebrates. Cyathaspididae. 432 FIELDIANA: GEOLOGY, VOLUME 13. Fig. 151. Anglaspis expatriata (X 2). A, rubber impression of type, inner side of dorsal shield, National Museum of Canada 10038; B, ventral shield and part of dorsal shield, inner sides, CNHM, PF 3666. ds, dorsal shield; ^, impressions of gill pouches; pfo, impression of fossa for pineal organ; sec, impressions of semicircular canals; vs, ventral shield. Referred specimens.—CNHM, PF 3665, a flattened dorsal shield and scales, in counterpart; PF 3666 (fig. 151,B), incomplete dorsal and ventral shields, inner sides; National Museum of Canada, 10039-40, CNHM, PF 3667, incomplete ventral shields; CNHM, PF 3668-69, 3671, shield fragments; PF 3670, scales. Occurrence.—Early Devonian, top of Mt. Sekwi, beside the Keele River, Northwest Territories, Canada (68° 28' N.; 128° 40' W.) (California Standard Company locality Z 29-61, 4474'). Diagnosis.—The length of the dorsal shield is about 24 mm., and that of the ventral shield is 20-23 mm. On both shields there are centrally 3-33^ dentine ridges per millimeter, and their crests are sharp and moderately high. The orbits and pineal organ are rather anterior in position; the orbital ratio is .14-. 15, and the pineal ratio is . Discussion.—Anglaspis expatriata is very similar to the British species, A. macculloughi. From the latter it differs in its more an- terior orbits and pineal organ, and usually in its smaller size. A. ex- patriata may have had rounded postero-lateral corners on the dorsal shield; in A. macculloughi these corners form pointed spurs. The. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Denison, Robert H. (Robert Howland), 1911-1985; Chicago Natural History Museum. Chicago : Chicago Natural H
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