ORTHOCERATII)^. 
47 
Orthoceras extenuatum ?, Barrande. 
1870. OHhoceras extenuatmn, Barrande, Syst. Sil. de la Boheme, vol.ii. 
Texte iii. 1874 (janvier), p. 502, pi. cccxci. ff. 1-4, 9-14, 18-21, 
pi. cccxcii. ff. 12-14, ? pi. cccxciii. f. 9, pi. cccct. ff. 4-7. 
Sp. Char. Section circular. Bate of increase very slow, about 
1 in 17. Septa regular and horizontal distant about ^ the diameter. 
Length of the body-chamber about 4 times the diameter of its base. 
Siphuncle subcentral. Surface ornamented by very fine, subregular, 
oblique raised striae, of which there are about 6 in a line. 
Remarl's. The specimen in the iS'ational Collection which may 
represent this species consists of a fragment, probably belonging to 
the body-chamber, as it exhibits no trace either of septa or siphuncle. 
The surface of the test is, however, well preserved in some places, 
and presents the same characters as the species to which I have, 
with some doubt, referred it. The transverse lines in the specimen 
before me are, if anything, closer than in Barrande’s species, but 
beyond that I can find no difference between the two forms. 
Horizon. Stage 7, “Upper Orthoceras-Limestone ” ( = Salopian ?). 
Locality. Malmo, Sweden. 
One verj’ imperfect example. 
Orthoceras amoenum, Barrande. 
186G. Orthoceras amcemim, Barrande, Syst. Sil. de la Boheme, vol. ii, 
Texte iii. 1874 (janvier), p. 306, pi. ccxxiv. ff. 5-7, pi. cccxcv. 
ff. 16-33, pi. cccc. ff. 14-16, pi. ccccv. ft’. 8-10. 
Sp. Char. Section circular. Bate of increase 1 in 7. Septa dis- 
tant about 4 the diameter ; regular and horizontal. Body-chamber 
well-developed and occupying nearly | the length of the shell ; its 
length equalling from 4 to 6 times the diameter of its base. The 
siphuncle is subcentral. The surface of the test is ornamented with 
very faint annulations, of which there are about two per line. 
Horizon. Etage E, bande e 1 ( = Salopian). 
Locality. Butowitz, Bohemia. 
Well represented in the Collection. 
Orthoceras inchoatum, Barrande. 
1866. Orthoceras inchoatum, Barrande, Syst. Sil. de la Boheme, vol. ii. 
Texte iii. 1874 (janvier), p. 328, pi. ccix. ff. 8-12, ? pi. ccxxxix. 
f. 27, pi. ccclxviii., pi. ccclxix. 
Sp. Char. Section invariably circular. Bate of increase about 
1 in 10. The body-chamber, judging by fragments in different 
