BRACniOPODA. 



377 



on a low septal ridge (s) ; dorsal valve with a prominent septum 

 (5) supporting a spoon-shaped central i)rocess (r) ; oral lamellae 

 long and slender [o). Foramen angular, cardinal process dis- 

 tinct {j). Fossil, 9 species. Carb. — Permian (Magnesian lime- 

 stone.) Germany and England. 



Fig. 177. laternal cast.* 



Fig. 178. Section. 



Pentameeus, Sowerby. 



Etymology, pentameres, 5-partite. 



Synonym, Gypidia (conchydium), Dalman. 



Type, P. Knightii, PI. XV., Fig. 22. Fig. 179. 



Shell impunctate, ovate, ventricose, with a large incurved 

 beak ; valves usually plaited ; foramen angular ; no area or 

 deltidium ; dental plates [d) converging, trough-like, supported 

 on a prominent septum (*) ; dorsal valve with two contiguous 



Longitudinal, 



F:g. 179. 



Transverse section. 



longitudinal septa (e s) opposed to the plates of the other 

 valve. 



Oral lamellae have been detected by Mr. Salter in P. liratus ; 



* Ventral side of cast, showing the V-shaped cavity of the dental plates, and the 

 impressicns of brancliial veins, accompanied by arteries (after King), 



