MANUAL OF THE MOLLUSCA. 
Type, A. Bohemicum, Barr., Fig. 5. 
Shell flask-shaped, smooth, transversely or 
longitudinally striated, or ornamented with 
annular folds, or plicated. The terminal cham- 
ber (7) occupying the space above the air- 
chambers (s), and extending down one side of 
nearly the whole length of the shell in the 
form of a wide and deep cavity, which is 
embraced by the decurrent edges of the in- 
complete septa (four or five in number). This 
cavity also communicates at its base with a 
small siphuncle which traverses the minute 
apical air-chambers. Aperture of shell simple. 
The wide ventral cavity of Ascoceras is of 
the same nature as the large lateral siphuncle 
4? of Cameroceras. 
Fig. 5. Distribution, 16 species. Lower—Upper 
Diagram of Ascoceras Q7},,44 : d : 
(after Barrande). ae ian. Bohemia, Nor WeNe England, Ca: 
; nada. 
GLOSSOCERAS, Barrande, 1865. 
Hiymology, glossa, a tongue, and ceras. 
Type, G. gracile, Barrande. Upper Silurian. Bohemia. 
Shell similar to that of Ascoceras, but the dorsal margin of the 
aperture is extended in the form of a ligulate projection, sub- 
triangularly rounded at the end, and recurved towards the inte 
ylor of the shell. 
This process gives rise to a distinct. lobe on each side of the 
opening, which is analogous to that wkich exists in Hercoceras, 
Ophidioceras, and in certain species of Phragmoceras and Gom- 
phoceras. 
Distribution, 2 species. Middle and Upper Silurian. Anti- 
costi; Bohemia. 
APHRAGMITES, Barrande, 1865. 
Etymology, a, without phragmos, a partition; and the usual 
termination. 
Type, Ascoceras Buchii, Barrande. 
Shell, similar to that of Ascoceras, but the air-chambers are 
deciduous. 
Distribution, 2 species. Upper Silurian. Bohemia. 
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