316 
PALEONTOLOGY OF NEW YORK. 
in the form and characters of the siphuncle, as well as in the other elements of 
the shell, as to render the removal of the genus Bactrites to the Goniatitidoe 
undesirable. It seems to possess transitional features between the families of 
Goniatitidm and Orthoceratidse; and I prefer to arrange it, for the present at 
least, with the latter. 
Bactrites clavus, n. sp. 
PLATES LXXXIV, FIG. 15; CXIII, FIGS. 1-5. 
Shell slender, straight, regularly and gradually enlarging to the aperture. 
Transverse section elliptical. Dorso-ventral diameter the longer, having a 
ratio of 2 to 3 with the lateral diameter. Tube subcarinate on the dorsal (?) 
side. Apical angle a little more than 1°. Initial extremity unknown. 
Chamber of habitation well developed, having a length of more than six 
times the dorso-ventral diameter at the last septum, regularly enlarging to 
the aperture. Air-chambers regular, with a depth of three mm., or equal 
to the lateral diameter of the tube, from which they do not vary perceptibly 
in the length of sixty mm. 
Septa thin, smooth, moderately concave along the lateral diameter, and 
with a concavity equal to an arc of 140° in a dorso-ventral direction. The 
sutures form a broad retral curve over the lateral faces of the tube, extend¬ 
ing forward over both the ventral and dorsal sides. Immediately over the 
insertion of the siphuncle they curve more or less abruptly backward, form¬ 
ing the “dorsal lobe,” which corresponds to a similar feature in Goniatites, 
and probably marks the ventral side of the shell. The sutures meet in an 
obtuse angle at the carina along the dorsal (?) side. 
Siphuncle small, submarginal, indenting the septa, having a diameter of 
one-half of one mm. Its elements in the interseptal spaces are unknown. 
Test and surface ornaments not preserved on any of the specimens. 
Internal mould smooth, with the sutures but slightly impressed. 
An individual, preserving a portion of the chamber of habitation and 
twenty-three air-chambers, has a length of ninety-five mm.; with dorso-ven- 
