FOSSIL FAUNA. 153 



PLATE LXVII. 



Fossil Shells of Brachiopoda, &c. 



Fig. 1. A species of Badiolites {R. agariciformis, of M. D'Orbigny), from the Cretaceous strata of 

 France. This genus is only known in a fossil state ; it belongs to the same group 

 of shells (order, Rudistes) as the Spherulites and Hippurites : the lower valve is 

 conical, and much larger than the upper, which is slightly convex ; it is deeply chan- 

 nelled longitudinally. 



Fig. 2. Smooth valve of a species of Corbula (Gorbula galllca, of Lamarck) ; abundant in some 

 of the Eocene deposits of the Paris basin. 



Fig. 3. A single valve ; the inner surface is shown in the figure, of a remarkable genus of shells 

 {Crania personata, of Lamarck), frequently occurring attached to Echinites and other 

 bodies of the white chalk. 



Fig. 4. A species of Terebratula [T. diphya, of Lamarck). The shells of this genus belong 

 to that division of moUusks termed Brachiopoda (arm-feet), from their having 

 internally two spiral fleshy arms developed from the sides of the alimentary orifice. 

 These organs are supported by shelly processes, curiously' modified in different genera, 

 which often occur in a fossil state. Although the fossil Terebratulas are very numerous, 

 the recent species are but few, and are inhabitants of the seas oflf Australia. They form 

 two natural groups ; in the one the shells are smooth, but perforated all over with 

 minute openings or foramina; and these are often filled with a dark substance, which 

 is the carbonized soft parts : in the other division the shells are plicated or furrowed, 

 and are not foraminiferous.' The Spirifers, another group of Brachiopoda, have a pair 

 of internal spiral appendages. 



Fig. 5. Terebratula coaretata, of Parkinson. Bradford clay, Wilts. 



Figs. 6, & 7, show the internal structure of recent Terebratulse from New Holland. The 

 complicated shelly apophyses which supported the arms are quite perfect. 



Fig. 8. Terebratula triquetra, of Parkinson (T. diphya, of Lamarck); another example of the 

 species, fig. 4. 



Figs. 9, & 10. Different parts of the same specimen of a brachiopodous bivalve belonging to 

 the genus Productus, so named from the lengthened or produced form of the convex 



1 On the structure of shells the reader should consult the admirable papers of Dr. Carpenter, in the British Association 

 Reports. 



