140 GUIDE TO THE FOSSIL INVEETEBRATE ANIMALS. 



Gallery J. E. Lee, and have been described by the Eev. G. F. Whid- 

 borne in the Monographs of the Palaeontographical Society. 

 Here are most of the genera already observed in the Carboni- 

 ferous series. Among lameUibranchs Cardiola retrostriata is 

 important to the stratigrapher. 

 Table-case Silurian. The Ludlovian Age is represented by fossils 

 from Ledbury, Ludlow, and Kendal, the Wenlockian by 

 fossils from Dudley and Benthall Edge, the Valentian by a 

 few Bellerophons from the Llandovery beds. In addition to 

 the Palaeozoic genera already mentioned, one may see here 

 Pterinaea (Fig. 75 h), Orthonota, and Grammy sia among the 

 common lameUibranchs. The gastropods include numerous 

 forms allied to EuomphaluSy one of them, Polytropina, 

 preserving the operculum, also the slightly curved JEcculiom- 

 2)halus, and Trematonotus (Fig. 75/), the ''pierced back" 

 ally of Bellero2:)Jion. The Amphineura are represented by 

 Helmintliochiton. 



Fig. 75. — Lower PalEeozoic LameUibranchs and Gastropods, a, Cardiola 

 interrupta ; b, Pterinsea Danbyi ; c, BelleropJion cambriensis, a recon- 

 structed side view; d, Platyceras [Acroculia'} \haliotis ; e, Maclurea 

 Logani, the type-specimen, a, b, d, and/, are Silurian from the Wen- 

 lock beds of Dudley ; e is Ordovician, from the lower Llandeilo of Ayr- 

 shire ; c, Cambrian, from the Upper Festiniog beds of Dolgelly. a and 

 c are nat. size ; b, d, e, f, | natural size, (Table-case 16.) 



Table-case Ordovician. The rocks of this Epoch, formerly classed 

 as Lower Silurian, have furnished molluscan fossils from the 

 Caradoc, Llandeilo, and Arenig divisions. Those exhibited 

 come mostly from Wales and Shropshire, but there are a 



