Fig. 



174. Strophomena analoga. Fragment of the interior of the ventral valve, to show the different 



muscular impressions and foramen. 



175. „ „ Fragment of the beak, to show the aperture. 

 1/6, 177- Lept/Ena TRANSVERSALis, Dal. 177 section. 



178. ,, „ Interior of ventral valve. 



179. 5, • „ Interior of dorsal valve. 



180. „ ■ „ View of the double area. 

 181,182. „ ^rawswersa, Pander = genus P/ec^am6owiYe5, Pander. 



183. „ Bavidsonii, Eng. Deslongchamps. Lias, France. 



184. ,, oblonga, Pander. 



185. „ ,, Interior of dorsal valve. 



186. Davidsonia Verneuili, Bouchard. 



187. „ „ Interior of ventral or dental valve, from the specimen figured by M. de 



Verneuil (Geol. of Russia, pi. xv, fig. 9). 



188. „ „ Interior of ventral valve, showing the vascular impressions, &c. 



189. „ „ Interior of dorsal valve (enlarged), from the specimen described by 



M. de Koninck, and now in the British Museum. 



190. 191. „ „ A specimen in the collection of M. de Koninck. 



192. „ Bouchardiana, de Kon. E.xterior, natural size. 



193. „ „ Interior of the dorsal valve, from the original specimen figured by 



M. de Koninck, and now in the British Museum. 



194. 19.5. KoNiNCKiNA Leonhardi, Wissman, sp. 



196. „ „ Interior of dorsal valve, with a portion of the spiral lamella preserved. 



197. J, ,, Translucid specimen made thinner by acid, and seen from the ex- 



terior of the ventral valve. 



198. „ „ Section of the valves. These last three enlarged illustrations were 



drawn and forwarded to me by Mr. Suess, of Vienna. 

 198 bis, 199. Chonetes lata, Sow., sp., from Ludlow. 



200. „ n. sp. The interior of the dorsal valve, from the Devonian Limestone of 



Nehou, and showing besides the muscular scars, the reniform im- 

 pressions, V, which prove that this section should be classed 

 among the Productid<s. 



201. „ „ ,, ? Interior oi ventral valve, from a species from the Eifel. 



202. „ * „ Interior of dorsal valve, from a specimen from the Eifel. 

 203 — 20r). Stkophalosia excavata = genus Orthothrix, Geinitz. 



206. „ Goldfusii, Munster, sp., showing the large area and deltidium. 



207. „ Morrisiana, King. Interior of dorsal valve, enlarged ; M, fragment of the 



ventral valve, to show the articulation of the hinge. 



208. „ Goldfusii. Internal cast. 



209,210. „ Morrmana, King. /, point of attachment. 



211. „ Gerardi, King. (Note. — All the specimens from which the illustrations of 



Strophalosia have been drawn, were lent me by 

 Professor King, and form part of the Collection 

 of Queen's College, Galway.) 



