KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 23. N:o |2. 21 
more so on the former. The outline of both the ventral and the dorsal side has nearly 
the same curvature. On the interior surface of the necklike part there are some fine oblique 
strix impressed from the destroyed inside of the shell. They are imbricate and when 
seen in a section they are serrated. (Pl. VI f. 1b, ec.) 
There are two regular septa and three sigmoid ones. The first of the latter is 
low and does not reach to the median axis of the shell; the second is at a distance of 
7 millim. from this, and the third is close to the second. Both are so much curved in- 
ward, that they surpass the median axis, and that the body chamber at their greatest 
bend is only 3 mm. in breadth, whilst the curve is 8 mm. The siphuncle is situated 
near the ventral side, and the scar of the Nautiloid siphunele on the first septum is cir- 
cular. Length of the shell 20 mm., breadth 11 mm., shorter diameter 9 mm. 
This species is related to the Bohemian Ascoceras Deshayesi, having nearly the same 
sort of transverse screwlike ribs. It is, however, much shorter and of a more ovate shape 
and the body chamber much more widened below. 
In the red limestone at Holms hallar in Wamlingbo there has been found a single, 
but fragmentary specimen of an Ascoceras, which as far as can be seen, is a mutation of 
Asc. cochleatum or may range as a variety derived from it. It is, at present at least, 
with so scanty material not possible to find whether it differs in any greater degree. The 
scerewlike ribs are nearly identical and on the thin shell there are only a few indistinct 
longitudinal lines sculptured. It measures 37 mill. in length and 17 millim. in breadth, 
the lesser diam. being 12 millim. 
2. Ascoceras dolium n. 
Pla £ 26. 
Only the Ascoceras stage has been found. Distr. The Museum of Stockholm keeps 
two specimens from the stratum b near Wisby. 
Shell short, obese, ovate, ventral side considerably more curved than the dorsal side. 
In a transverse section the shell has an oval shape. 
The surface is transversally ribbed by dense imbricating lines highest at their in- 
ferior rim and sloping upwards. There are six such lines on a length of 4 millim:s. On 
the ventral side they are bent downwards, on the dorsal side again they are quite as 
straight as on the largest lateral surfaces and at right angles with the longitudinal axis 
of the shell. Near the truncated end they are more narrow and dense and this seems 
also to have been the case near the aperture, which is broken. 
There are two regular septa beneath the sigmoid ones; the first is the septum of 
the truncature which is thick and joins with the shell, having been strengthened from 
within after the decollation. The next is parallel with the septum of the truncature and 
abuts on the inside of the dorsal side without any sigmoid curve. It is distant from 
the truncature quite as much as the ventral edge of the uppermost sigmoid septum is 
distant from itself. Next we have three very thin sigmoid septa of which the second at- 
tams with its largest sigmoid curve a breadth of 10 millim:s, and 3 millim:s more are 
left there for the body chamber. At the broken top of the shell the septum has nearly 
four millim:s where it is at most narrow and 7 millim:s at the sides, the largest diameter 
