220 
PALAEONTOLOGY OF NEW-YORK. 
285. 17. ENDOCERAS DISTANS (». sp.). 
Pl. LVII. Figs. 1 a, b. 
Teretely 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 I 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 a. 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 Murchison and 
de Verneuil on the Palaeontology of Russia and the Ural Mountains. 
Klein, 1731, Descr. tubulorum marinorum, PI. 2, fig. 1 a, b (c, d, exclusis). 
7 e espece d’Orthoceratites, Breyn, 1732, Dissert, de Polythalamiis, PI. 5, fig. 1-4. 
Orthoceratites duplex, Wahlenberg, Act. Soc. Sc. Upsal, Vol. viii, p. 80. 
— spiralis, Fischer, 1829, Bull, de Moscow, p. 323. 
— — Pander, 1830, Beitr. zur geogn. 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. 
— — Kutorga, 1837, Beitr. zur geogn. Dorpat, pag. 32, pi. 5, fig. 9. 
— giganteus. Id. Ib. pi. 6, fig. 6 (non id Sowerby). 
— spiralis, Eichwald, 1840, Sil. Syst. in Esthland, p. 92. 
— duplex, Quenstedt, 1840, Neues Jahrb. fur Mineralogie, p. 262. 
— — Troost, 1841, Sixth Geol. Rep. Tennessee, p. 10. 
— — Verneuil, 1845, Pal. Russ. & Ur. Mountains, pag. 351, pi. 24, f. 7; & pi. 25, f. 2 a b. 
