168 GUIDE TO THE FOSSIL INVERTEBEATE ANIMALS. 



Gallery Ljitoceras lineatuni this habit was again lost, especially in 

 old age, and only the fine ribs are seen. The two species 

 Amalthcus margaritcUus and Paltoplcuroceras \A7ncdtheiis\ 

 sinnatum should be noted for their peculiar ornament, 

 and because they are characteristic of the Marlstone. 



Among specimens from the Upper Lias the black 

 ammonites from Whitby catch the eye. They include the 



a h c 



cl e f 



Fig. 95. — Ammonites, a, Trachyceras Aon, Upper Trias, side view, b, the 

 same, front view, showing folded septum, c, Lytoceras fimbriatuni, 

 Middle Lias. cZ, e, Coeloceras Blagdeni, Inferior Oolite. /, Phylloceras 

 heterophyllmn, Upper Lias, shell partly removed to expose sutures. 

 Less than natural size. 



Table-case primitive form Cynibites carivMhts. Close by is the type- 

 specimen of Haiyoceras falcifcrum. A specimen of this 



Wall-case species in the Wall-case has an aptychus in the body- 

 chamber. Here, too, are large specimens of Phylloceras 

 lutcro'pliylhvm in section, as well as polished ones showing 

 the foliated sutures (Fig. 95/). 



