46 G. LINDSTRÖM, THE ASCOCERATID.E AND THE LITUITIDAE. 
Fig. 
PLAST E 
Ascoceras manubrium n. 
1—2. Sections of apices with six and seven septa from Sandarfve. 
3. Nucleus of the end of another specimen with the sutures of six sigmoid septa and one Nautiloid sep- 
tum, seen from the ventral side. 
4. Longitudinal section showing the two strata, of which the shell is composed, a. the exterior one, c. 
interior lining it. 
53. Longitudinal section near the apex, a. the exterior shell, b. the septum of the truncature, c. the interior 
lining stratum, 1, 2, 3 sigmoid septa forming the innermost dark stratum, near the ventral side. 
6. Interior view of the bottom of the body chamber longitudinally sectioned along the dorsal side. Spe- 
cimen from Sandarfve kulle magnified. 
7. Idealized view of the same, as seen from above, to show how the seven septa are arranged above each 
other in the bottom. Ventral side down. 
8. A model of an Asc. manubrium, sectioned along the median line, to elucidate the structure and ar- 
rangement of the septa. 
Ascoceras fistula n. 
9. Ideal view of its three sigmoid septa seen from the ventral side. 
10. The third septum, shown as free and, as it were, dissected out from the shell, to exhibit the large va- 
cuum in the middle. 
11. The same, lateral aspect. 
Ascoceras manubrium n. 
12, 13, 14. Different views of a specimen with a fragment of the Nautiloid still left in situ, from Sand: 
arfve kulle. Fig. 14, dorsal view. 
15. Transverse section of the Ascoceratid part near the upper margin. 
16. View of the Nautiloid apex; same specimen. 
17. Longitudinal section of the same, the Ascoceras having not yet any septa, thus being in the »Aphrag- 
mite»-stage; a. the siphuncle of the Nautiloid continued into the siphuncle of the Ascoceras, b. si- 
phuncele of the lowest septum of the Nautiloid. 
18. A joint of a specimen from Linde klint; a. magnified section of the shell. 
19. Ornamentation of the same. 
20. Longitudinal sections of a Nautiloid specimen from Linde. 
21. Ditto from Sandarfve. 
22--25. Different views and longitudinal section of a Nautiloid from Sandarfve, younger stage. 
26—28. Still younger specimen, same locality. 
29. Longitudinal section and 30—31 details of ornamentation of very small specimen from Linde klint. 
32. Ascoceras bohemicum BARR. nat. size from Hoburg. 
33. View of its inferior apex and a. transverse section near the ventral side, showing the four septa. 
