PLATE XVI. 



Zone of Aegoceras angulatum. 



Fig. 1. Aegoceras Liassicum, d'Orbigny. Side view, natural size. Lower Lias, 



Redcar, Yorkshire. My collection. 

 Procured at Whitby. 

 2. — — Siphonal area of the same fossil to show 



the absence of the ribs in this region. 

 This specimen resembles two large examples of this species contained in the 

 d'Orbignian type collection in the " Jardin des Plantes," Paris. 



