GOMPHOCEEATID^ 
229 
axis at the last septum is to the transverse as 4 : 3. These propor- 
tions vary a little in different parts of the body-chamber. The latter 
occupies about one half of the total length of the shell. The plane 
of the apertural surface is inclined at a considerable angle to that 
of the last septum. There is a slight swelling in the body-chamber 
just below the ventral (smaller) orifice. The larger orifice is of a 
broadly elliptical form, of which the diameters are in the ratio of 
4:3; the channel connecting the larger with the smaller orifice is 
narrow, anrl, in fact, it is closed at a point near the larger orifice, 
after which it gradually widens to form the smaller orifice. The 
borders of the latter are very prominent, and form a recurved beak- 
like process. The septa are rather wide apart, their mean dis- 
tance from each other being equal to about ^ of the ventro-dorsal 
diameter. The siphuncle is situated very near the ventral border, 
and its elements are nummuloidal. The test is thin in the septate 
portion of the shell, but thicker at the body-chamber and around 
the aperture ; its surface is composed of thin superimposed lamellaB, 
which have a direct upward imbrication. The striae of growth cor- 
responding with this structure of the test are irregularly spaced ; 
they cross the sides of the shell in a broad curve, forming a shallow 
sinus on the dorsal margin and a narrow tongue-like lobe (concave 
towards the aperture) in the median line of the ventral border. 
Remarhs. Among British species G. imbricatum finds its nearest 
ally in G. arcuatum^ from which it may be distinguished chiefly by 
the character of its ornamentation, which separates it also from G. 
Broderipi, G. rex, and other Bohemian species of a similar habit. 
Horizon. Etage E ( = Salopian). 
Loccdities. Butowitz, Prague, Bohemia. 
Fairly well represented in the Collection. 
Gomphoceras longum, Barrande, sp. 
1847. Phragmoceras longum, Barrande, Haidiager, Berichte fiber die 
Mittheil. von Freund, d. Naturwiss. in Wien, Band iii. p. 269. 
1867. Phragmoceras longum, Barrande, Syst. Sil. de la Boheme, vol. ii. 
pt. i. p. 213, pi. lix. 
Bp. Char. This species is strongly curved, though the apex is at 
a considerable distance from the body-chamber. The section is 
oval, the smaller extremity corresponding with the concave border 
of the shell. The ventro-dorsal is to the transverse axis as 3:2. 
The increase is in the ratio of 1 : 4 upon a length of 40 millim. of the 
septate part of the shell. The body-chamber is not very largely 
