. First[-fourth] annual report of the Geological survey of Texas, 1889[-1892] Edwin T. Dumble, state geologist. CARBONIFEROUS CEPHALOPODS. 351 or dorsal zone is only 35 mm. in diameter, showing that the next internalwhorl must have been very small compared to the outer one. The sutureshave the typical form, with narrow, angular ventral saddles. The septa aredivided by a median ridge internally, as in other forms of this genus. The principal differences between this species and its nearest congener,Ephip. bilobatum of Europe, lies in the extraordinarily rapid increase of thelateral diameters of
. First[-fourth] annual report of the Geological survey of Texas, 1889[-1892] Edwin T. Dumble, state geologist. CARBONIFEROUS CEPHALOPODS. 351 or dorsal zone is only 35 mm. in diameter, showing that the next internalwhorl must have been very small compared to the outer one. The sutureshave the typical form, with narrow, angular ventral saddles. The septa aredivided by a median ridge internally, as in other forms of this genus. The principal differences between this species and its nearest congener,Ephip. bilobatum of Europe, lies in the extraordinarily rapid increase of thelateral diameters of the whorls by growth and the enormous breadth of thelast whorl. The lateral lobes are not so long, and the saddles at the umbili-cal shoulders not so deep in the specimen described, but this may be more amatter of age. Fragments of the shell still remain on the cast of the livingchamber, and these are smooth. The Nautilus clitellarius, as figured by De Verneuil* is a small shell withopen umbilici not at all similar to the fossil described above or to the trueEpiph. bilobatum or clitellarium and we propose
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