. Bulletins of American paleontology. New Guinea Ammonites: Westermann & Getty 283. Text-fig. 19. — Adult septal suture of Irianitcs cf. /. moermanni (Kruizinga) 2, at approximately 25 mm whorl height. ( Leiden, st. 126222). largest whorls. Tlie umbo-lateral bullae persist for some time mov- ing somewhat higher on the inner flank, and finally fuse with the lateral ttibercles, situated high on the lateral edge, to form short bladelike ribs. The strong secondaries, in twos with frequent single intercalaries, cross more or less straight and undiminished over the broad venter. The outer
. Bulletins of American paleontology. New Guinea Ammonites: Westermann & Getty 283. Text-fig. 19. — Adult septal suture of Irianitcs cf. /. moermanni (Kruizinga) 2, at approximately 25 mm whorl height. ( Leiden, st. 126222). largest whorls. Tlie umbo-lateral bullae persist for some time mov- ing somewhat higher on the inner flank, and finally fuse with the lateral ttibercles, situated high on the lateral edge, to form short bladelike ribs. The strong secondaries, in twos with frequent single intercalaries, cross more or less straight and undiminished over the broad venter. The outer 11/^-2 whorls are therefore typically 'coronate'. The body chamber occupies nearly one whorl in the largest more or less complete specimens measuring 80-90 mm diameter, but the aperture is not preserved in any. Taking into consideration several large fragments, the terminal diameter was approximately 90-120 mm. The adult septal suture (Text-fig. 19) is weakly incised only. L is broad and short-rooted; the adjacent simple ('second') lateral saddle L/Uo is about as high as the external saddle E/L and only slightly higher but much broader than the oblique 'third lateral' saddle U0/U3, which is separated by the small simple lobe Uo; the suture drops sharply adjacent to the umbilical seam with one or two small oblique elements probably belonging to U3; the internal suture consists of a dissimilar saddle pair, the inner one being about twice as large as the outer one, separated by a large almost straight 'internal lateral' lobe (U„?); the lobe adjacent to the seam (? Uj) is approximately as deep as the 'internal lateral' lobe. Comparison and dimorphic corresponderice. — AXlhough. super- ficially resembling Stemniatoceras or, if fully grown, Teloceras (both probably best classified as subgenera of Stephanoceras), this form is clearly distinguished by the planulate and tabulate inner. Please note that these images are extracted from scanned page images that may have been digitall
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