E2^D0CERATID^. 
149 
Tar. percostatum, var. nov. (Fig. 16.) 
1857. OrtJwceras vaginatum, Boll, Beitrag zur Kenntniss der Silur. 
Ceph., in Arcliivfur die Xaturkunde von Mecklenburg, p. 9, Taf. i- 
ff. 1 c, 1 d. 
1866. Endoceras {Orthoceras) trochleare, Barrande, Syst. Sil. de la 
Boheme, vol. ii. Texte iii. 1874, p. 710, pi. ccccxli, ff. 22-24. 
The variety is distinguished from the species by the coarser 
character of its principal ornaments, which consist of very numerous 
and distinct rounded annulations, separated by interspaces of equal 
width. The annulations form a shallow sinus on the siphuncular 
side of the shell, and where they arch gently upwards on either side 
of it they are necessarily oblique to its long axis. The distance 
of the annulations from summit to summit varies from 2 to 6 lines 
according to the development of the individual measured. Both the 
annulations and the spaces dividing them are, as in the species, 
covered with fine, close-set, raised lines, which are more crowded 
(especially in the interspaces) than they are in the species. 
Horizon. Limestone ( = Arenig). 
Localities. Kin nekuUe (Westrogothia), Sweden. Xoriudiholm (?), 
Norway. 
'Well represented in the Collection. Several of the specimens 
from Kinuekulle were presented by J. E. Lee, Esq., F.S.A., F.G.S. 
Endoceras cancellatum, Eichwald, sp. 
1842. Orthoceratites ccr«ce//«^?<5,Eichwald,I)ieUrweltRiisslands, Heft 2, 
p. 67, Tab. iii. ff. 9, 10. 
1845. Orthoceratites vaginatiis, Murch., Vern.,and Keyserl. G^ol. de la 
Russie d’Europe, vol ii. Raleont. p. 349, pi. xxiv. ff. 6, a, b. 
1849. Orthocei'atites vaginatiis, Quenstedt, Die Cephalopoden, p. 42, 
pi. i. f. 3. (Copied from Eichwald, loc. cit.') 
1860. Cycloceras cancellatum, Eichwald, Lethsea Rossica, vol. i. Se- 
conde Section de I’ancienne Periode, p. 1226. 
1869. Oiidioceras cancellatum, Karsten, Die Verstein. des Uebergangs- 
gebirges in dem Gerollen der Herzogthiimer Schleswig und Hol- 
stein, p. 49, tab. xvii. tf. 2, a, h, c. 
1885. Orthoceras {Endoceras) vaginatum, F. Roemer, Letheea erratica, 
in Dames and Kayser’s Palseont. Abhandl., Band ii. Heft 5, p. 126 
(373), Taf. lx. [xxxii.] ff. 1, a, h, c. 
[P1837. Orthoceratites sulcatus, Fischer de 'Waldheim, Oryctogr. de 
Moscou, p. 125, pi. ix. ff. 1, 2.] 
Sp. Char. Shell straight. Rate of increase about 1 in 17. Sec- 
tion subelliptical, the ratio of the two diameters being as 21 ; 19. 
Septa numerous, slightly undulating, with a downward sweep on 
