BRACHIOPODA. 



217 



Fig. 116. Ter: Evansii. Dav. 



TEREBRATELLA, D'Orbigny. 



Type, T. dorsata, Gmel. (= Magellanica, 

 Chemn.) PI. XV. fig. 7. Kg. 115. 



Shell smooth or radiately plaited ; dorsal valve 

 longitudinally impressed; hinge-line straight, or 

 not much curved ; beak with a flattened area on each 

 side of the deltidium; foramen large; deltidium 

 incomplete ; loop attached to the septum (*). 



Animal like Terelratula ; the spiral lobe 

 of the brachial disk becomes very diminutive 

 in some species, and is obsolete in Morrisia , 

 and T. Cumingii. Distr. excluding sub- 

 genera, 16 sp. Cape Horn, Valparaiso (90 ' 

 fins.), New Zealand, Japan, Ochotsk, Spits- 

 bergen, Labrador. Fossil, 16 sp. Lias . 

 U.S. Europe. In T. crenulata and Evansii 

 (fig. 116) the dorsal septum sometimes projects so far as to touch the oppo- 

 site valve, but in other examples it remains undeveloped. (Davidson.} 



Sub-genera. Trigonosemus (elegans) Konig. Syn. Delthyridaea (pecti- 

 niformis) M'Coy. Fissirostra, D'Orb. Ex. T. Palissii, PI. XV. fig. 8. 

 Shell finely plaited, beak prominent, curved, with a narrow apical foramen ; 

 cardinal area large, triangular ; deltidium solid, flat ; cardinal process very 

 prominent. Distr. 5 sp. Chalk, Europe. 



Lyra (Meadi) Cumberland, Min. Con. 1816. PI. XV. fig. 6. Syn. Te- 

 rebrirostra, D'Orb. Rhynchora, Dalman.* Shell ornamented with rounded 

 ribs ; beak very long, divided lengthwise internally, by the dental plates ; 

 loop doubly attached ? Distr. 4 sp. cretaceous : Europe. Three species of 

 similar form are found in the Trias of St. Cassian. 



Magas (pumila) Sby. Pig. 117. Shell 

 smooth, conspicuously punctate, dorsal valve 

 impressed, foramen angular, deltidium ru- 

 dimentary; internal septum (s) promi- 

 nent, touching the ventral valve; re- 

 flected portions of the loop disunited (I). 

 2 sp. IT. Green-sand Chalk. Europe. 

 The recent Ter. Cumingii, of New Zealand, Fig. 117. M. pumila. 



* The name Rhynchora was given by Dalman to the Ter. costata. Wahl. (= T. 

 pectinata, L.) on the supposition that it was identical with Sowerby's T. Lyra ? and as 

 no specimen could be found with a long beak, an artificial one was manufactured for 

 it, of which there is a cast in the Brit, M. The second species of" Rhynchora," Ter. 

 spatulata, Wahl. has no beak whatever : in shape it is.. like an Argiopf. but measures 

 an inch each way. The ventral valve is a simple bent plate with the teeth at the 

 angles; the dorsal valve is flat, with a very wide hinge-plate, and sockets at the angles, 

 whilst a single septum projects from the centre, with portions of a loop attached, 



