﻿BRITISH FOSSIL CEPHALOPODA. 



Plate XVII. 



Fig. 



1. Orthoceras (Endoceras) Brongniartii. — From the Bala Beds, Desertcreat. 



In the Museum of Practical Geology. Portlock's figured specimen, a, the 

 septal surface. 



2. Orthoceras araneosum. — From the Wenlock Shale, Buildwas. In the Museum 



of Practical G-eology. a, part of the surface magnified. 



3. Orthoceras (Endoceras) festijstans. — From Lower Silurian Beds, Worthin. 



In the British Museum, a, the septal surface. 



