CEPHALOPODA. 
453 
This species, both in its exterior characters and internal arrangement, is 
quite distinct from any other form known among the collections from the New 
York formations. In many of its characters it is closely similar to G. retrorsus, 
von Bucii. In the manner of its septa it is very similar to the var. lingua and 
var. typus of that species, as represented by Sandberger, Verstein. des Rhein. 
Schichtensystems in Nassau, p. 109, tab. 10, fig. 20, and 10 a, figs. 4, 5; while 
the var. undulatus , pi. 10 a, figs. 17, 19, represents the surface-markings and the 
revolving carime. The var. auris, pi. 10, figs. 11-13, is represented in the 
young of our species. 
Formation and locality. In the arenaceous shales of the Portage group, on the 
shores of Lake Erie, in Chautauqua county, N. Y. 
Goniatites simulator. 
PLATES LXIX, FIGS, 1, 2; LXXIV, FIG. 8. 
Goniatites simulator. Hall. Descriptions of New Species of Goniatidae, p. 2. May, 1874. 
“ “ “ Twenty-seventh Rep. N. V. State Mus. Nat. Hist., p. 133. 1875. 
“ “ “ Illustrations of Devonian Fossils : Cephalopoda, pi. 69, figs. 1, 2. 1876. 
Shell discoid, lateral faces gentlj T curving from the umbilical side to the margin 
of the periphery, which is very symmetrically rounded. The transverse and 
lateral diameters, measured at the first quarter volution of the air-chamber } 
are about as eighteen to forty-two. 
Volutions, three or more, closely coiled, leaving a moderately wide umbili¬ 
cus in which less than hall the width of each volution is exposed; inner 
margins of the volutions abruptly, and in the older ones almost rectangularly, 
curving into the umbilical depression. Transverse section symmetrically 
semi-elliptical, with the base deeply indented by the inclosed inner volution. 
The enlargement of the volutions to the first quarter of the outer chamber is 
regular and somewhat rapid, the last septate volution increasing in its outer 
half from twelve to seventeen mm. The diameter of the septate portion of 
the tube, at one volution back of the broken margin of the outer chamber, as 
compared with the width of the latter, is about as twelve to twenty-three. 
The chamber of habitation is preserved for about one-quarter of a volution, 
and continues with about the same rate of enlargement as the preceding volu- 
