236 

 Terebratula — continued. 



Piedmontana. . subrotund, subdepressed, transversely striated, 



biangulated upwards ; umbo elevated, beak recurved. 

 quadrijida. . triangular, depressed, dilated ; four angles upwards, 



beak short. 

 angulata. . subtrigonal, ventricose, upper margin deeply grooved, 



with three acute angles, longitudinally striated. 

 mullicarinata. . large, round, pectiniform, with numerous cari- 



nated ribs ; margin not grooved. . 3 inches long by 3j. 

 tetraedra. . gibbous ; upper valve deeply grooved ; in the groove 



and sides three or four angulated ribs ; beak incurved. . 



Aynhoe. 

 plicata. . subtetraedral, plicated, not grooved ; five or six ribs 



obtuse at the base, angulated at the margins, beak short. 

 canalifera. . trigonate, gibbous, longitudinally sulcated with a 



deep groove ; hinge straight, beak large, striated perpen- 

 dicularly to the hinge. 

 Icevicosta. . trigonate, gibbous, grooved in the sides ; a sinus 



in the middle of the larger valve, and a broad rib in the 



less, both smooth ; striae transverse ; hinge straight ; 



beak short. . Bemberg. 

 intermedia. . subtetraedral, dilated, plicated, grooved ; four 



plaits to the groove and five to the sides ; beak short. 

 aZa^a. . subtrigonate, dilated; a deep sinus upwards, beak 



short. 

 concinna. . globose, subsinuate, plicated ; five to seven raised 



plaits in the middle, ten to twelve on sides ; beak produced. 

 media. . subtrigonate, gibbous, sinuate, plicated, six plicae in 



the middle, seven or eight on the sides ; beak subrecurved 



. . Aynhoe. 

 pectita. . subrotund, larger valve subconvex, smaller rather flat, 



with radiating plaits ; beaks produced, recurved. . Horn- 



ingsham. 

 cardium. . elongato-ovate, convex, plicated, with thick longitu- 

 dinal rounded grooves, beak rather prominent. 

 difformis. . trigonate, dilated, subdepressed ; margin unequal, 



windingly bent in the middle ; beak rather produced. . 



Havre. 

 lyra. . subglobose, contracted forwards ; beak so produced as 



to equal in length the smaller valve. . Horningsham. 

 Menardii. . globose, truncated in the base, larger valve having a 



deep longitudinal groove ; margin sinuously deflected. . 



Coulaines. 

 decussata. . subpentagonal, subconvex ; larger valve canalicu- 



lated ; striae fine, decussating ; beak rather produced, 



foramen large. 

 spinosa. . globose, dilated, with small spinous grooves ; beak 



very short, pointed. 

 spathica. . subtrigonate, subglobose, smooth ; upper margin 



grooved, beak pointed, subproduccd. , From the hills to a 



great extent near Mons. 



