ORTHOCEEATID^. 
125 
The most remarkable feature in this species is its rapidly 
increasing diameter. I have already pointed out its resemblance 
in this respect to the 0. stnatulum of Sowerby, under the descrip- 
tion of that species. The latter is, however, easily distinguished 
from the present form by its generally coarser sculpture, and especi- 
ally by its possessing strong longitudinal riblets. 
I think it is questionable whether these two species should not be 
removed from the genus Ortlioceras, on account of their exceedingly 
conical form : but as our knowledge of them is incomplete, neither 
the body-chamber nor the siphurcle of either of them being known, 
it would be hardly judicious to remove them from their present 
position until further information about them can be obtained. 
Horizon. Posidonomyen-Schiefer (Steinkohlenformation) \ Culm- 
measures. 
Localities. Herborn, near Dillenberg, Nassau ; Marburg. — The 
specimen from Marburg was presented by J. E. Lee, Esq., E.G.S. 
Well represented in the Collection. 
Orthoceras striolatum, G. & E. Sandberger. 
? 1831. Orthoceratites striolatm, H. von Meyer, Nova Acta Leop.- 
Carolin. vol. xv. pt. ii. p. 77, Taf. Ivi. ff. 1-12 (not Taf. Iv.) 
F 1832. Orihocera striolata, von Dechen, Handb. der Geognosie von H. 
T. de la Beche, p. 530. 
1842. Orthoceratites striolatm, dArchiac & de Veraeuil, Trans. Geol. 
Soc. 2nd ser. vol. vi. p. 345, tab. xxvii. IF. 5, 5a. 
1852. Orthoceras striolatmn, Giebel, Fauna der Vorwelt, p. 251. 
1854. Orthoceras striolatum, F. A. Roemer,Pal?eontographica, Bandiii. 
p. 49. 
1856. Orthoceras striolatum, G. & F. Sandberger, Die Verstein. Nassau, 
p. 165, Taf. xix. ff. 3, 3 a-h. 
1879. Orthoceras striolatum, Giimbel, Geogn. Beschreib. des Fichtel- 
gebirges, in Geogn. Beschreib. des Konig. Bayern, Abtli. iii. p. 498_ 
1882. Orthoceras striolatum, Kayser, Beitr. z. Kenntn. von Oberdevon 
und Culm am Nordrande des rheinisch. Schiefergebirges, in Jahrb. 
der konigl. preuss. geolog. Landesanst. und Bergakad. zu Berlin 
fiir das Jahr 1881, p. 75. 
1884. Orthoceras striolatum, H. Woodward, Geol. Mag. new ser. 
dec. iii. vol. i. p. 539. 
Sp. Char. Shell straight, elongate. Bate of tapering about 1 
in 5. Septa rather convex, horizontal, near together, two in the 
‘ See Geinitz, ‘ Die Steinkohlen Deutschlands,’ Munich, 1865, pp. 201 and 
238. 
