96 BRACHIOPODA. 



Terebratella subpentagonaj Koch, 1837, Beitr. zur Kenn. Ool. 

 p. 21.pl. l.f. 8. 



D'Orb. Prod. i. p. 221. 

 Fossil. Lower Lias. Germany. 



5. TRIGONOSEMUS. 



Shell plaited, beak produced, cvirved, with a narrow apical 

 foramen ; area large, triangular, flat, marked by the outline of 

 the flat deltidium ; cardinal process very prominent. 



Trigonosemus (elegans), Konig, 1822, Icones Foss. p. 3. f. 73- 



Davidson, 1852, Mon. Cret. p. 28. 

 Delthyridsea (pectiniformis), M'Coy, 1845, Griffith's Irish Curb. 



Fossils (unpublished). 

 Fissurirostra (recurva), D'Orb. Ter. Cret. iv. p. 133. t. 520; Jnn. 



Sc. Nat. 1848. 

 Fissirostra, D'Orb. 1849, Cours Elem. Palceont. p. 89. 



1. Trigonosemus elegans. B.M. 



Shell oval, striato-costate ; strife 30-40, often intercalated; 

 dorsal valve slightly convex, longitudinally depressed in front ; 

 beak much produced, rather recurved ; area very large, trian- 

 gular, nearly flat ; foramen small and narrow, apical ; loop elon- 

 gated, reflected, doubly attached; cardinal process veiT promi- 

 nent. Lon. 11, lat. 9, alt. 5 Unes. 



Trigonosemus elegans, Konig, 1825, Icones Foss. p. 3. pi. 6. 



f. 73. 



Davidson, Mon. Cret. p. 29. pi. 4. f. 1-4. 

 Terebratula elegans, Defr. 1828, Diet. Sc. Nat- hii. p. 157. 

 Terebratula recui-va, id. p. 161. 

 Fissurirostra recuna, elegans, et pectita, D'Orb. 1847. Ter. Cret. 



iv. p. 133-136. t. 520. 



Fossil. Chalk. England (Nor^vich) ; Belgium (Ciply) ; France. 



2. Trigonosemus pectiniformis. B.M. 



Shell trapezoidal, depressed, radiately ribbed; ribs straight, 

 dichotomous ; ventral valve elevated in the middle, depressed at 

 the sides ; beak recurved ; area nearly as wide as the shell, deep, 

 sharply margined; deltidium triangular, flat; foramen minute, 

 apical ; dorsal valve triangular, depressed in the centre ; cardinal 

 process prominent ; loop elongated, reflected, doubly attached. 

 Lon. 6, lat. 6, alt. 3 Unes. 



Terebratuhtes pectiniformis, Schlotheim, 1813, Taschb.vu. p. 113. 



