386 
SUPPLEMENT. 
Barrande regarded this family as equal in importance to the large 
families of the NautiUdcB and the Goniatitidce, and gave it a col- 
lateral place as the third family of the Bohemian Cephalopoda. He 
Fig. 84. 
A, schematic view of the interior o^' Ascocer as manubrium, Lindstr., showing the 
structure and arrangement of the septa : si, siphuncle ; d.t, duct that coiii- 
municates with the siphuncle of the Nautiloid portion of the shell {n, 
fig. F). B, schematic view of three sigmoid septa of Ascoceras fistula, 
Lindstr., seen from the ventral side. C, view of the third septum of the 
same species, shown as free, as if detached from the shell, to e.vbibit the 
large central lacuna. D, the same, viewed laterally (the siphuncular ori- 
fice is seen at the bottom of all these figures). E, longitudinal section of a 
specimen of Asc. decipiens, Lind.str., from Sandarfve kulle (hill), with four 
regular septa above the sigmoid ones. F, schematic view of Asc. decipiens, 
represented as if complete; n, the IS^autiloid portion of the shell. G, lon- 
gitudinal and median section from the concave to the convex side of 
Choanoceras mutahile, Lindstr., showing the interior of the shell, with the 
outlines of the incomplete septa ; si, siphuncle. H, fragment of the same 
species, reduced to about ^ natural size. — All the figures are copied from 
Lindstrom’s plates ; A-D are reduced by camera from about J to ^ natural 
size ; E-G are the size of the original figures 
has been followed in this respect by Fischer in his recent ‘ Manuel 
de Conchyliologie.’ But nearly all the other authors, who have 
^ The above figures are taken from plates hi., v., and vi. of Lindstrbm’s 
memoir on ‘ The Ascoceratidae and Lituitidse of the Upper Silurian Formation 
of Gotland ’ (Stockholm, 1890). 
