. Revision of the Amphibia and Pisces of the Permian of North America. ind. The planes of the sides have an angle of nearlyforty-five degrees with each other and are broadly rounded in their union. MORPHOLOGICAL REVISION 117 The dorsal surface is rather deeply pitted, the depressions rounded or ovalwith reticulating ridges between them. The under surface is smooth, andappears not to have been underlaid with lateral expansions of the of this shield, on the under side, there are nine spine dilatations, thefirst six or seven complete in the specimen. They are thin, flat plates,apparen
. Revision of the Amphibia and Pisces of the Permian of North America. ind. The planes of the sides have an angle of nearlyforty-five degrees with each other and are broadly rounded in their union. MORPHOLOGICAL REVISION 117 The dorsal surface is rather deeply pitted, the depressions rounded or ovalwith reticulating ridges between them. The under surface is smooth, andappears not to have been underlaid with lateral expansions of the of this shield, on the under side, there are nine spine dilatations, thefirst six or seven complete in the specimen. They are thin, flat plates,apparently co-ossified with the rather slender spines above, directed nearlytransversely, with a less angle of declivity than has the nuchal or scapularshield. The outer extremities are narrowed or obtusely pointed, their uppersurface beveled both in front and behind for the dorsal shields. Their sur-face is smooth throughout. The dorsal shields are rather stout, elongate bones, rounded on theirouter extremities, pitted on their dorsal surface like the nuchal shield, form-. FiG. 45. A. DissoTophus {Otocwlus testudineus). No. 4343 Am. Mus. X }4. Lower view of thoracic region, showing interclavicle, clavicles, cleithra, and scapula. B. Same; lower surface of a fragment, showing the femur, tibia, and fibula. C. Dissorophus multicinctus. No. 4593 Am. Mus. X }i. Lower view of a portion of vertebral column. D. Same; upper view of a portion of vertebral column, showing dermal plates overlying and alter- nating with the expanded neural spines. E. Same; anterior view of same fragment shown in C and D, showing the relation of dermal plates to neural spines. ing a rather uniform arc of a circle, with less steepness on the sides thanthat of the nuchal shield. These shields, thick in their middle line, thinnedalong their anterior and posterior margins, leave a space of from two tofour millimeters between their adjacent borders, in which the smooth sur-face of the spinal expansions is visible. Vert
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Keywords: ., bookcentury1900, bookdecade1910, bookidc, booksubjectpaleontology
