GOMPHOCEEATTD^. 
221 
Gomphoceras cylindricum, Barrande. 
1847. Gomphoceras cylindrieum, Barrande, Haidiuger^ Bericlite iiber 
die Mittheil. von Freund, d. Naturwiss. in Wien, Band iii. 
p. 269. 
1867. Gomphoceras cylindrieum, Barrande, Syst. Sil. de la Boheme, 
vol. ii. pt. i. p. 309, pi. Ixxix. 
Sp. Char. This species is small. The transverse section is gener- 
ally circular in the septate part of the shell, but flattened a little in 
the body-chamber, in some specimens. The body-chamber occupies 
in some examples -1, in others |- of the total length of the shell. The 
aperture, which is very distinctly T-shaped, is a little inclined to- 
wards the ventral side. The larger orifice is very narrow and 
curved in conformity with the contour of the shell : it is scarcely 
perceptibly lobed. The channel connecting it with the smaller 
orifice is long and very narrow. The greatest distance between the 
septa equals about -1 of the shell-diameter ; they are perfectly 
horizontal. The siphuncle is situated about midway between the 
ventral margin and the centre ; its elements are cylindrical, and 
the width is to the height as 2 : 3. The test is covered with very 
fine, close-set, somewhat irregular striae of growth, which have a 
slight concave inflexion at the extremity of the smaller orifice, 
caused by the projecting lobe of the latter. 
Remarks. This species may be recognized by its small size, cylin- 
drical form, and extremely contracted aperture. 
Horizon. Etage E (= Salopian). 
Locality. Dlauha Hora, Lochkow, Bohemia. 
Well represented in the Collection. 
Gomphoceras incola^ Barrande. 
1867. Gomphoceras incola, Barrande, Syst. Sil. de la Boheme, vol. ii. 
pt. i. p. 313, p]. Ixviii. fP. 9-19, pi. Ixxxi. fi*. 7, 8, ? pi. xcii. f. 15. 
Bp. Char. The shell in this species has a very distinct curvature 
on the ventral side, while upon the dorsal it is only very slightly 
convex, and often appears quite straight. The transverse section is 
circular, but it is noticeable that in this species, as also in the 
greater part of its congeners, the dorsal side is flattened at the 
aperture, although the section in the septate part of the shell may 
be circular. The body -chamber appears to occupy about 1- or of 
the length and more than half of the total bulk of the shell. The 
aperture is a little inclined in relation to the vertical axis, and its 
larger orifice is much elevated and extended laterally. Both this 
