KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 23. N:o |2. 29 
9. Ascoceras collare n. 
PI TVeng ED. 
Only two specimens of the Ascoceras stage have been found at Gannviken in Gröt- 
lingbo. 
Shell ovate-oblong, dorsal side nearly straight, the ventral one convex. Neck short, 
scarcely a fourth of the total length. The weathered surface does not show any trace of 
the ornamentation. There are five sigmoid septa. Their interior surface has impressions 
of short, horizontal, interrupted and wavy lines, caused by the mantle (fig. 6, a). The 
necks of the septa are so much developed as to be nearly as large as in Asc. bohemicum 
and in Choanoceras. The aperture of the siphuncle on the inferior surface of the trun- 
cature is surrounded with a similar neck like a prominent ring and this is closed from 
within by secreted matter. As in ÅAsc. manubrium there has been a basal tube on the 
superior surface of the septum, but in this species it is narrow and so oblique that it 
leans against the septum. 
Length of the shell 43 millim., dorso-ventral diam. 17 wmillim., minor diam. 12 millim. 
10. Ascoceras lagena n. 
Pl. IV fig. 17—24, Pl: VI fig. 4: 
1888 Ascoceras LIinNDsTR. On the genus Ascoceras Barr. Geol. Magazine p. 532 with figure. 
Of this shell both stages in connexion have been found at Samsugn and Klints in 
Othem. 
The Nautiloid stage. Regularly cylindrical and faintly curved, surface ornamented 
by a network of intercrossing longitudinal and transverse strie or folds, the longitudinal 
ones being in some parts more strongly expressed. The narrow, tubiform siphuncle is situ- 
ated close to the ventral side. The septa are regularly concave, the concavity increasing with 
the size of the shell and it is somewhat oblique as its dorsal edge is placed much higher 
than the ventral one. The necks are short. The septa are, as common with the Ascoce- 
rata, much irregularly distantiated. In the youngest specimens (f. 21) they are nearly 
equally distributed, but in a somewhat larger (fig. 19) there is great inequality, the 
distance varying from 2 millim. to 6 millim. In the piece which yet is coherent with 
the Ascoceras the distance between the two lowest septa is 10 millim. and between the 
second and the bottom of the Ascoceras 8 millim. ”The' diameter of the shell being 10 
millim. 
The Ascoceras stage. The Ascoceras shell is elongated, tumid, much curved, cre- 
scentshaped, the ventral side forming a convex arch and the dorsal one being concave. 
The neck is broken but has probably been long. The ornamentation partly resembles that 
of the Nautiloid (compare fig. 17 a and 22) consisting of narrow longitudinal folds crossed 
by finer lines making a mosaic of small quadrates, further down (fig. 17 b) the transverse 
folds predominate, much distantiated and prominent. The shell is very thin and seems 
to be but a direct continuation of the septum of the truncature. This septum is still thin, 
