300 
NAFTILOIDEA. 
of the shell, while the transverse striae are much closer together 
than in the present species. 
Horizon. Etage E ( = Salopian). 
Locality. Lochkow, Bohemia. 
Eairly well represented in the Collection. 
Cyrtoceras (Meloceras) pergratum, Barrande, sp. 
1867. Cyrtoceras pergratum, Barrande, Syst. Sil. de la Boheme, vol. ii. 
pt. i. p. 640, pi. cxcix. ff. 1-23. 
Sp. Char. Shell slightly curved ; upon a chord of 62 millim., 
subtending the concave side of a nearly complete specimen, the 
highest perpendicular is 4 millim. The shell tends to become 
straight in the upper part. The transverse section is circular. 
The increase in the septate part of the shell is in the ratio of 1 : 2, 
in a length of 25 millim. The length of the body-chamber amounts 
to about twice the diameter of the aperture, or |- of the total 
length of the shell. The aperture is a little inclined towards the 
convex side. The distance between the septa is equal to about 
I the diameter of the shell. The siphuncle is situated at a little 
distance from the centre, towards the convex border ; it is cylin- 
drical. The surface of the shell is ornamented with prominent 
annulations, about 1 line distant from each other where the shell 
has a diameter of 5 lines, the interspaces being about equal in 
width to the annulations. These coarser ornaments are covered 
with very fine transverse striae, following the direction of the ribs, 
and these are crossed longitudinally by a series of fine ridges, about 
5 of which are contained within the s^Dace of 1 line ; the latter do 
not appear to extend above the septate part of the shell. 
Remarlcs. I have already instituted a comparison between this 
species and M. cognatum under the descrij)tion of the latter. 
One cannot but be struck with the marked resemblance this 
species bears to Orthoceras didce, Barr., var. Barr. (pi. ccxcv.). 
We seem, in fact, to have reached in such species as this forms 
which connect Cyrtoceras with Orthoceras. 
Horizon. Etage E ( = Salopian). 
Localities. Kosorz, Lochkow, Wiskocilka, Bohemia. 
Eairly well represented in the Collection. 
