53 



TEREBRATULA Sella. 



TAB. CCCCXXXVIL— /^. 1. 



Spec. Char. Subquadrangular, convex; front 

 considerably elevated, narrow, emarginated 

 when old; sides depressed, slightly rounded. 



\y HEN young this shell is rather trigonal in consequence 

 of the length of the sides and roundness of the front ; as 

 it grows older it becomes squarer, the front being more 

 produced as well as more derated ; the beak is very 

 slightly curved ; the length and breadth are nearly 

 equal ; the edges always sharp. 



A characteristic shell of the Kentish Rag Stone ; a 

 series of specimens were collected in the celebrated 

 quarries of that stone at Chart, near Ashford, in Kent, 

 by A. Power, Esq. several yearfl ago. I have it also 

 from Sandgate, where a mass of Stone was found by 

 Mr. Goodhall, containing several full sized individuals, 

 one of which contained crystallized Quartz. The speci- 

 men figured was said to come from Hythe. 



TEREBRATULA obtusa. 



TAB. CCCCXXXVII.— /^. 4. 



Spec. Char. Suborbicular, rather depressed ; 

 front broad, elevated ; edge obtuse. 



X HE lesser valve is rather wider than long ; but the 

 projection of the beak of the other valve makes that 

 longer than wide ; their surfaces are equally and re- 

 gularly convex, except near the edges, where they are 

 rather suddenly bent so as to produce a squarish margin. 

 I have only seen one individual of this Terebratulu ; 

 it was sent from Cambridge along with many specimens 

 of T. biplicata, one of which has been figured upon 

 Tab. 90. 



TAB. CCCCXXX.VU.—figs.2andB. 



These are representations of a young and a full grown 

 specimen of T. biplicata, in views that a])peared neces- 

 sary to point out the difference between it and T. pero- 

 valis, and also between it and the shells formerly con- 



