290 PAUEONTOLOOY OF NEW-YORK. ' "^ 



285. 17. ENDOCERAS DISTANS ( n. sp.). 



Pi.. LVII. Figs. I a, b. 



Teretcly cylindrical, very gradually tapering ; septa thick, distant one half the diameter 

 of the shell, moderately convex ; siphuncle marginal, large ( more than two fifths the 

 diameter of the shell ) ; external surface 1 section circular. 



The specimen figured is compressed towards the larger extremity, which gives it the 

 appearance of enlarging more rapidly than it really does. The siphuncle is large, but is 

 apparently of equal width throughout. The distance of the septa is much greater than in 

 Orthoceras amplicameratum, and the siphuncle much larger and lateral. In these particulars 

 it is clearly distinct from any described species. 



In the dimensions of the tube, position and size of the siphuncle, it corresponds precisely 

 with a specimen of 0. duplex from Sweden ; but the septa are more distant than usually 

 represented in that species. Our species will probably prove to be a true Endoceras, judging 

 from the dimensions of the siphuncle, though the specimen under consideration apparently 

 contains no embryo tube.* 



Fig. 1 o. A weathered cast of a fragment of this species. 



Fig. 1 b. Transverse section of the smaller extremity of the same, showing the large siphuncle. 



Position and locality. This species has been found only in the upper part of the Trenton 

 limestone at Turin, Lewis county. 



* The following references and synonyms of the Orthoceratites duplex, are given from the work of Mukchison and 

 DK Verneuii. on the Palsontology of Russia and the Ural Mountains. 



Klein, 1731, Descr. tttbulorum marinorum, PI. 2, fig. I a, b (c, d, exclusis). 



7* espice d' Orthoceratites, Breyn, 1732, Dissert, de Polythalamiis, PI. 5, fig. 1-4. 



Orthoceratitet duplex, Wahlenbero, Act. See. Sc. Upsal, Vol. viii, p. 86. 



— tpiralu, Fischer, 1S29, Bull, de Moscow, p. 323. 



— — Pander, 1830, Beitr. zuigeogn. Russland, pag. 109, pi. 30, fig. 1. 



— — Fischer, 1837, Oryct. de Gouv. de Moscow, pag. 125, pi. 10. 



— duplex, HisiNGER, 1837, Leth. Suecica, pag. 28, pi. 9, fig. 1. 



— — KuTOROA, 1837, Beitr. zur geogn. Dorpat, pag. 32, pi. 5, fig. 9. 



— giganteut. Id. lb. pi. 6, fig. 6 (non id Sowerby). 



— tpiralu, EicHWALD, 1840, Sil. Syst. in Esthland, p. 92. 



— duplex, Qdenbtedt, 1840, Neues Jahrb. fur Mineralogie, p. 262. 



— — Troost, 1841, Sixth Geol. Rep. Tennessee, p. 10. 



— — Verneuul, 1845, Pal. Russ. & Ur. Mountains, pag. 351, pi. 24, f 7 ; & pi. 25, f 2 a 6. 



