CTRTOCEKATID^. 
297 
45 millim., subtending the concave side of a nearly complete 
specimen, the highest perpendicular is nearly 7 millim. Transverse 
section circular. The increase in diameter, which is somewhat 
variable, is in the ratio of 1 : 6 in a length of 35 millim., measured 
in the septate part. The body-chamber occupies nearly of the 
total length of the shell. The aperture is inclined towards the 
convex side, where it forms a wide sinus. The distance between 
the septa is equivalent to about ^ the diameter of the shell. 
The siphuncle is situated on the concave border, but without 
touching the test ; it is slightly inflated between the septa. The 
test is ornamented with small and regular transverse striae, having 
a direct imbrication ; these are covered with fine lines, running in 
the same direction ; very flne longitudinal striae are also present in 
some examples. In addition to these ornaments the test when 
well preserved exhibits very beautiful colour patterns, the intensity 
of which is increased by wetting. These consist of bands of which 
the white tint contrasts with the brown of the test. The bands 
form a zigzag pattern made up of rounded and pointed arches, the 
former directed towards the aperture, the latter away from it. There 
are about seven of these arches in the circumference of the shell. 
Remarhs. The species that comes nearest to this is M. dehile^ 
Barr. sp. (pi. clxxvii.), but it is less arcuate, dilates less rapidly, and 
has a cylindrical siphuncle. 
Horizon. Etage E (= Salopian). 
Locality. Kosofz, Bohemia. 
Eairly well represented in the Collection. 
Cyrtoceras (Meloceras) virgula, Barrande, sp. 
1848. Cyrtoceras virgula, Barrande, Haidinger, Berichte iiber die 
Mittheil. von Freund, der Naturwiss. in Wien, Band iv. p. 209. 
1852. Cyrtoceras virgula, Giebel, Fauna der Vorwelt, Band iii. Abth. i. 
p. 209. 
1867. Cyrtoceras virgula, Barrande, Syst. Sil. de la Boheme, vol. ii. 
pt. i. p. 694, pi. clxxiii. ff. 8-15. 
ySp. Char. Shell strongly curved, especially in the region of the 
aperture. Upon a chord of 27 millim., subtending the concave side, 
the highest perpendicular is 7 millim. The transverse section 
is oval, the ratio of the two diameters being as 4 : 3. The rate of 
increase, measured in the septate part of a young example, is in the 
ratio of 2 to 5 in a length of 22 millim. : it is less than this in adult 
shells. The body-chamber occupies about | of the total length of 
the shell. The aperture has a sinus upon the concave border, and a 
