BBACHIOPODA. 215 



jxteud through a whole " system" of rocks, and abound equally in both 

 lemispheres ; others (like Spirifera striata) range from the Cordillera to the 

 Ural mountains. One recent Terebratula (caput-serpentis] made its appear- 

 ince in the Miocene Tertiary ; whilst others, scarcely distinguishable from it, 

 ire found in the Upper Oolite, and throughout the Chalk series and London 



FAMILY I. TEREBRATULID^E. 



Shell minutely punctate; usually round or oval, smooth or striated; 

 central valve with a prominent beak, and two curved hinge-teeth ; dorsal 

 ralve with a depressed umbo, a prominent cardinal process between the dental 

 ockets, and a slender shelly loop. 



Animal attached by a pedicle, or by the ventral valve : oral arms united 

 o each other by a membrane, variously folded ; sometimes spiral at their 

 extremities. 



Fig. 111. Terebratula vitrea, Born. 

 TEREBRATULA, (Llhwyd.) Brug. Lamp-shell. 



Eiym. Diminutive of terebratus, perforated. 



Syn. Lampas, Humph. Gryphus, Muhlfeldt. Epithyris, Phil. 



Types, T. maxillata, PI. XV. fig. 1, (= Ter. minor-subrubra, Llhwyd. 

 Anomia terebratula, L.) T. vitrea, fig. 3. 



Shell smooth, convex ; beak truncated and perforated ; foramen circular ; 

 leltidium of two pieces, frequently blended ; loop very short, simple, attached 

 y its crura to the hinge- plate. (Tig. Ill, A.) 



Animal attached by a pedicle ; brachial disk tri-lobed, centre lobe elon- 

 'ated and spirally convoluted. (Pig. Ill, B.) The young of T. diphya 

 Pygope of Link) has bi-lobed valves, (PI. XV. fig. 2.) ; when adult the 

 obes unite, leaving a round hole through the centre of the shell. 



Distr. 1 sp. Medit. 90250 fathoms on nullipore mud. (Forbes.} 



Fossil, 100 sp. Devonian . World-wide. 



