108 GUIDE TO THE FOSSIL INVERTEURATE ANIMALS. 
Gallery LutoccraH /inealam. Lliis hal)it was a^^aiii lo.sl, e.specially in 
old age, and only tlic tine ribs are seen. The two .species 
AmalthruH marnariiaim and P(tUn2)levrorcras fijiina/ian 
shonld he noted for their i)eciiliar ornament, and hecan.se 
they are characteristic of the IVIarlstone. 
Among specimens from the Ui)per Lias the black 
ammonites from 'Whitby catch the eye. They include the 
a b c 
d c f 
Fig. 95. — Ammonites, a, Trachyccras Aon, Upper Trias, side view, b, the 
same, front view, showing folded septum, c, Lytoceras jhnbriatum, 
Jliddlo Lias. d,e, Coeloceras Ufapdciii, Inferior Oolite. /, Phylloceras 
hetcrophylluin, Upper Lias, shell partly removed to expose sutures. 
Less than natural size. 
Table-case primitive form Cyvibites carinatus. Close hy is the type- 
specimen of JIarpoccras faldfcrum. An example of this 
Wall-case species in the Wall-case has an apt}'chus in the hody- 
chamber. Here, too, are large specimens of Phylloceras 
lidcrophylliim in section, as well as polished ones showing 
the foliated sutures (Fig. Oo/). 
