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ORMOCERAS REMOTISEPTUM, (n. species.) 

 Plate 4, fig. 3. 



Cylindrical, gradually tapering; septa moderately convex, distant 

 half the diameter of the tube ; siphuncle excentric, farge, swelling 

 moderately between the septa, and but slightly contracted at the junc- 

 tion of the septa ; character of the external surface unknown. 



The specimen described is a fragment which is worn down through 

 the centre of the siphuncle. The proportions of this part of the fossil 

 and the great distance of the septa contrast very strongly with the 

 Ormoceras tenuifilum and with the other known species of the genus. 



This species occurs in the higher part of the Trenton limestone, near 

 Watertown, Jefferson county. (State Collection.) 



ENDOCERAS LATIVENTRUM, (n. species.) 

 Plate 5, fig. 1, a, b. 



Cylindric or conical, somewhat rapidly tapering, septa very slightly 

 convex, distant from each other about one-sixth of the diameter of the 

 tube ; siphuncle large, entirely lateral, diameter towards the smaller 

 extremity greater than one-third the diameter of the entire tube ; em- 

 bryo tube smooth, slender towards the smaller extremity. 



This species is easily distinguished from the E. proteiforme in any of 

 its stages by the more rapid diminution of the tube, by the entirely lat- 

 eral position of the siphuncle, and the closer arrangement of the septa. 

 The fragment described is something more than a foot in length, and is 

 from the central part of the individual, neither the apex or outer cham- 

 ber being preserved. The embryo tube, which is visible near the apex, 

 is slender and gradually tapering. 



Fig. 1 a. The specimen natural size, showing the embryo tube above 

 the middle. 



Fig. 1 b. A section showing the position and size of the siphuncle. 



This species occurs in the lower part of the Trenton limestone, near 

 Lowville, in Lewis county. The only specimen known is the one here 

 . described, which is placed in the State collection. 



COLPOCERAS, (new genus.) 



Gr. xoXtfos, sinus, and xepus, cornu, in allusion to the deep sinus in the 

 septa. 



Cylindrical or sub-cylindrical, septa oblique to the axis of the shlll, 

 regularly arched on the dorsal side, and bending downwards in a deep 

 sinus towards the mouth on the ventral side. 



