﻿BRITISH FOSSIL CEPHALOPODA. 



Plate XVIII. 



Fig. 



1. Cyrtoceras compressum. — From the Lower Llandovery, Thrave. In the 



Museum of Practical Geology. 



2. Ibid. — From the Lower Ludlow, Ledbury. In the collection of Dr. G-rindrod. 



3. Lituites ibex. — From the Upper Ludlow, Ludlow. In the Museum of Prac- 



tical Geology. 



4. Ibid. — From the same locality. In the Museum of Owens College, Manchester. 



a, the septal surface. 



5. Ibid. — From the Lower Ludlow, Leintwardine. In the Museum of Practical 



Geology. [The apex is too little curved.] 



6. Cyrtoceras precox. — From the Tremadoc Slates, Garth. In the British 



Museum. 



7. Ibid. — From the Tremadoc Slates, Llanerch. In the Museum of the Uni- 



versity College for Wales, Aberystwith. Salter's type. 



8. Orthoceras hungaricum. — From the Bala Shales, Haverfordwest. In the 



Museum of Practical Geology. 



9. Orthoceras xit. — From the Wenlock Shale, Dudley. In the British Museum. 



10. Orthoceras Barrandei. — The specimen referred to by Salter as Gomphoceras 



liratum. From the Lower Ludlow, Aymestry. In the Woodwardian 

 Museum. Front view. 



11. Ibid. — From the Wenlock Shale, Dudley. In the British Museum. Side view, 



showing the undulating aperture and contortion in youth. 



12. Ibid.? — A flattened pair of septal chambers, showing siphuncle, a, and two 



pits, b, c, with vascular marks. From the Wenlock Limestone, Dudley. 

 In the Woodwardian Museum. 



13. Cyrtoceras intermedium? — From the Wenlock Series, Dudley. In the 



British Museum. 



14. Ophidioceras articulatum. — From the Lower Ludlow, Malvern. In the col- 



lection of Dr. Grindrod. a, enlarged view of the surface. 



15. Ibid. — From the Lower Ludlow, Ludlow. In the Ludlow Museum. 



16. Ophidioceras geometricum. — From the Lower Ludlow, Ludlow. In the 



British Museum, a, enlarged view of the surface. 



