Foerste.] 
278 
[May 1, 
extremity, was found in the same locality. The specimen has a 
vertical diameter of 95 mm. and is marked by oblique, low, trans- 
verse annulations, of which five fall in a length of 50 mm. The shell 
varies from 1 to 1.5 mm. in thickness, and shows numerous coarse 
transverse striae, following the direction of the annulae. The char- 
acter of the striae is so distinct from that of C. subcompressum 
as unhesitatingly to indicate a distinct species (PI. vn, fig. 16). 
Orthoceras (eu-orthoceras ?) virgulatum, Hall? 
(PLATE VII, FIG. 5.) 
A single specimen found at Soldiers’ Home, near Dayton, Ohio, 
is referred to this species. Should it prove to be distinct, the name 
tenui-siphonatum is suggested. It is 26 mm. long, and contains in 
that length, eleven chambers and twelve septa. The septa are all 
about 2.5 mm. apart, and are moderately concave, forming an arc 
of about 84°. The siphon very narrow, being about .8 mm. wide 
near the upper part of each chamber, tapering gradually towards 
the lower septum, and rapidly at the upper septum to a diameter of 
about .5 mm. The siphon also does not seem to be perfectly sym- 
metrical on all sides, but held in one position, it shows a straight 
or even slightly concave outline within each chamber, while the 
opposite side is convex in outline. Turned at an angle of 90° the 
siphon shows bilateral symmetry, the outline line on each side be- 
ing as described when the size of the siphon was stated. The sur- 
face of the Ohio form is not known, and the number of septa and 
the character of the siphon of the New York form, seem also un- 
known . 
Orthoceras (eu-orthoceras?) rectum, Worthen, var. junior, 
(plate vii, FIGS. 1, 2.) 
A small fragment was found, at Hanover, Indiana, in which the 
septa are 7 mm. apart, while the shell has a diameter of 15 mm. 
The septa are quite strongly concave, forming an arc of about 123°. 
The siphon is central, but a section of the specimen did not reveal 
the siphon in any recognizable form between the septa. In a speci- 
men 25 mm. long, the rate of tapering of the specimen was scarcely 
appreciable. 
In a specimen associated with this form, perhaps for no very good 
reason, the smaller end has a diameter of 17.4 mm., and the larger 
