LITUITIDiE. 
13 
Ophidioceras rudens, Barrande. 
1867. Ophidioceras {Lit.) rudens, Barrande, Syst. Sil. de la Boheme, 
vol. ii. pt. i. p. 183, pi. xlv. ff. 13-24. 
1877. Ophidioceras rudens, Barrande, ibid. Siipplem. et Serie tardive, 
pi. cccclxxviii. Case ii. 
Sp. Char. The straight piece in this species is very short, as in its 
congeners of the Bohemian basin, and is not more than from 10 to 
12 lines in length. The number of volutions is from 4 to 5, and 
their breadth increases very slowly. The transverse section is ellip- 
tical, the concave side being a little truncated, while the convex 
shows the flattened keel characteristic of the genus. The body- 
chamber, including the straight part, occupies a little more than f 
of the external volution. The aperture is contracted by the deve- 
lopment of the dorsal and lateral borders, which are inclined to- 
wards the interior of the body- chamber. These form the Y-shaped 
oriflces already described in other species of Ophidioceras. The septa 
are very close together, their average distance upqn the sides of the 
shell scarcely amounting to 1 line. The siphuncle is placed at a 
little distance from the keel, and is composed of cylindrical elements. 
The surface of the test and of the cast is ornamented with numerous 
transverse annulations, each of which corresponds with a septal 
chamber. The annulations do not quite reach the ventral keel. A 
network of minute lines covers the test, and is chiefly developed 
upon the earlier volutions ; the lines extend over the keel, where 
they form a backwardly directed sinus. 
Eemarlcs. Ophidioceras rudens is distinguished from all allied 
forms in the Bohemian rocks by the greater number of its whorls, 
viz. 4 to 5 instead of 3. 
Horizon. Etage E, hande e 1 (== Salopian). 
Locality. Butowitz, Bohemia. 
Represented in the Collection by a single example. 
Ophidioceras tessellatum, Barrande. 
18()7. Ophidioceras {Lit.) tessellatus, Barrande, Syst. Sil. de la Boheme, 
vol. ii. pt. i. p. 186, pi. xcvii. ff. 13-li). 
8p. Char. The general appearance of this species strikingly recalls 
that of Ophidioceras simplex. The straight piece is short, but it is 
not perfect in any specimens seen. The number of volutions amounts 
to two, with part of a third. The transverse section is subtriangular, 
the concave side being scarcely impressed by the preceding whorl. 
