508 
It is plain that the coiled young represents the nepionic and 
neanic stages and that the aperture must have differed essentially 
in these stages and perhaps may have been open or else more like 
that of Cyclolituites. 
N6tling also demonstrates in his paper in the Zec¢schrif¢ that the 
earlier stages had compressed whorls, the abdomen broader than 
the dorsum, and also that the siphuncle was nearer the dorsum in the 
youngest stage observed, and gradually departed from this towards 
the centre, becoming dorsocentren in the ephebic or outstretched 
whorl. In old age it again changes its position and tends towards 
the dorsal side. Nd6tling has also shown that the siphuncle was 
ellipochoanoidal, consisting of short funnels and the usual porous 
sheaths, or that which corresponds to this part in the siphuncles of 
other forms. The structure of the siphuncle in the younger stages 
was, however, not described or figured. A list of the species ac- 
cording to Notling is as follows: Z. “tuuws, De Montfort; Z. per- 
Jectus, Wahlenberg; to this Holm added, ZL. Zornguisti, Holm, 
and gave very instructive figures of the two species already known. 
L. discors, Holm, has a broad dorsal crest in the lines of growth 
and aperture and is here referred to Ancistroceras, and LZ. appla- 
natus Remele. 
Angelinoceras, n. g. 
There are several species usually referred to Lituites which can 
neither be included in this genus nor in Ancistroceras or Holmiceras. 
These have open coils in the young, and the usual lituitean out- 
stretched free whorl in the ephebic and gerontic stages. The only 
species known to me are those described by Angelin and Lindstrom 
in their Hragmenta Stlurica. ‘The lines of growth, and the annuli, 
during the neanic stage, have curves similar to those of Cyclolituites 
in A. datus, viz., with deep ventral sinuses, crests at the abdomi- 
nal angles, deep lateral sinuses near the dorsum and dorsal crests. 
These curves change in the ephebic whorl, becoming less sinuous, 
but, beyond the fact that they differ very much from those of 
Ancistroceras or Lituites, they cannot be defined with accuracy from 
the figures given. 
The increase by growth is more rapid than in Lituites and less 
rapid than in Ancistroceras, in 4. /a¢us and in A. anguinus it 1s 
very slow throughout life. The ephebic whorl is extended with the 
usual lituitean curve and closely resembles in aspect, but not in the 
