GOMPHOCEEATID^ . 
223 
border, but without coming in contact with the test. The latter is 
ornamented with fine transverse lines which conform to the curva- 
ture of the shell, and these are crossed by very fine longitudinal 
lines. 
RemarTcs. Barrande observes that this species is remarkable 
amongst the Bohemian Cephalopods for the variations which it ex- 
hibits in almost all the elements of its shell — in the curvature, 
length of body-chamber, form of aperture, form of the elements of 
the siphuncle, &c. 
Honzon. Etage E ( = Salopian). 
Localities. Hinter Kopanina, Kosorz, Lochkow, Bohemia. 
Bepresented in the Collection by three examples. 
Gomphoceras rigidum, Barrande. 
1847. Gomphoceras rujidum, Barrande, Haidinger, Berichte fiber die 
Mittheil. von Freund, d. Naturwiss. in Wien, Band iii. p. 269. 
1867. Gomphoceras rigidum, Barrande, Syst. Sil. de la Boheme, vol. ii. 
pt. i. p. 326, pi. Ixxxiii. ffl 10-14. 
1877. Gomphoceras rigidum, Barrande, ibid. Suppl. p. 193, pi. dxv. 
ff. 24-27. 
Sp. Char. Shell straight, excepting that there is a slight inflation 
in the body-chamber in the region of the smaller orifice. The 
transverse section is circular. The rate of increase in the septate 
part of the shell is variable ; in one specimen measured it is 2 in 3, 
in another 1 in 3. The body-chamber is of medium size, and may 
be computed to have occupied about | of the total length of the 
shell. The aperture is T-shaped ; the small orifice is oval and leads 
by a very short channel into the larger orifice, which is of a sub- 
elliptical form ; the whole aperture is distinctly raised above the 
surface of the body-chamber. The distance between the septa is 
somewhat irregular ; but it amounts on an average to about the 
diameter of the shell. The siphuncle is situated at a little distance 
from the centre, towards the ventral or convex margin ; its 
elements are spheroids, of which the width is to the height as 5 : 3. 
A narrow longitudinal canal or tube is observed in the interior of 
the siphuncle, which, according to Barrande, represents the fleshy 
part of the siphuncle {cordon charnu), compressed and shrunken 
(pi. Ixxxiii. fif. 12, 14, he. cit.). The test is not preserved, 
Horizon. Etage E (= Salopian). 
Locality. Lochkow, Bohemia. 
Bepresented in the Collection by a single example. 
