254 
THE LIAS AMMONITES. 
Oolite of France and England we find Ancyloceras annulatum, d'Orb. ; in Germany 
Ancyl. haculatum, Quenst. ; and in the Kelloway Rock of England we have a third species, 
Ancyl. Calloviense, Morr. It is in the Cretaceous rocks where this genus attains its chief 
Fig. 166. — Ancyloceras Matlieroniarmm, d'Orb. 
development. Ancyloceras Mather onianum, d'Orb. (fig. 166), is from the Upper Neocomian, 
and Ancyloceras Pusosianmn, d'Orb. (fig. 167), is from the Lower Neocomian. 
Fig. 167. — Ancyloceras Puzosianum, d'Orb. 
Gems Baculina, d' Orhigny. — Shell straight, with a surface destitute of ornamenta- 
tion. Baculina resembles Baculites except in the lateral lobes being single-pointed. 
Genus Perisphinctes, Waag. — Shell in general discoidal, with a wide umbilicus and 
a round ventral edge. The sculpture consists of straight or oblique ribs, inclined forward, 
Fig. 168. — Perisphinctes Martinsii, d'Orb. 
in general polytomate (much divided), and without tubercles. Mouth-border simple or 
with auricles ; a circular contraction visible on the shell near the outlet at certain stages of 
