310 
PALAEONTOLOGY OF NEW YORK. 
Septa smooth, thin, moderately concave. Sutures straight ancl horizontal. 
Siphuncle subcentral, moniliform. 
Test not preserved. The internal cast shows some traces of a lamellose- 
striate surface. 
Internal mould smooth, with the sutures slightly impressed. 
An individual, nearly entire, has a length of 107 mm., with a diameter of 
twenty-five mm. near the aperture, and contains the chamber of habitation 
and nineteen air-chambers. 
This species, in general proportions, resembles 0. cochleatum, and is distin¬ 
guished by its smaller apical angle, somewhat deeper air-chambers, and its 
straight and horizontal septal sutures. 
Formation and localities. From sandstones of the Chemung group, south of 
Ithaca, N. Y., and at Warren, Pa. 
Ortiloceras fulgidum, n. sp. 
PLATE XC, FIGS. 2, 3. 
Shell straight, slender, regularly enlarging to the aperture. Transverse section 
subcircular. Apical angle 6°. Initial extremity unknown. 
Chamber of habitation small, regularly expanding with the general con¬ 
tour of the tube, having a length of once and a half the diameter at the 
last septum. Aperture slightly contracted, with the margin acute. Air- 
chambers regular; depth equal to three mm., and showing but little variation 
in a length of twenty-five mm. 
Septa smooth, thin, with a concavity equal to the depth of the air- 
chambers. Sutures straight and horizontal. 
Siphuncle small, subcentral; its remaining characters have not been 
observed. 
The test has a thickness of .5 mm. Surface marked by fine, rounded 
striae of growth. Internal mould smooth. 
A fragment, preserving the chamber of habitation nearly entire and twelve 
air-chambers, has a length of forty-five mm., with a diameter of six and ten 
mm., respectively, at the two extremities. 
