312 TEREBRATULID^. 



branch off to the septum ; foramen complete. 2 sp. Cal., Japan. 

 T. Californica^ Koch (cxxxv, 40). 



KiNGENA, Davidson, 1852. Posterior part of the reflected 

 portion of the loop broad, angulated, with the two angles bent 

 down on each side and joined to the septum directly (not to the 

 haemal or septal processes), forming a broad ring, only intersected 

 by the septum ; exterior granulated ; foramen entire. T. lima, 

 Defrance (cxxxv, 43, 44). Cret. ; Europe. 



MAGAS, Sowb., 1816. (Mannia, Dewalque, 1874 ) Shell smooth, 

 conspicuously punctate, dorsal valve impressed, foramen angular, 

 deltidium rudimentary ; internal septum prominent, touching 

 the ventral valve ; reflected portions of the loop disunited. 3 

 sp. U. Greensand — Chalk; Europe. Recent, 2 sp. New Zea- 

 land, Canaries. T. piimila, Sowb. (cxxxv, 48, 49). 



RHYNCHORA, Dalm., 1828. Like Magas, but hinge-margin long, 

 straight, the large valve with an area. Cretaceous. T. costata, 

 Dalm. 



MAGASELLA, Dall, 1870. Shell with the reflected portions of 

 the apophyses united, forming a loop. Comprises most of the = 

 recent species of Magas. T. Uvansii, Dav. 11 sp. N. Zea- 

 land. 



ISMENIA, Gray, 1863. (Frenula, Dall, 1871.) Shell externally 

 resembling Terebratella ; apophj^ses broad and short, attached 

 first by the septal process to a short stout septum, then recurved, 

 the broad posterior edges of the reflected portion touching and 

 blending with the septal processes and the adjacent part of the 

 haemal processes, forming a funnel-shaped ring, into which the 

 septum does not project ; the lateral loops of the apophyses 

 remain open in the adult. Brachia without a median spiral lobe. 

 Jieceut; T. sang uinea, Chemn. Fossil; Ismenia pectunculus, 

 Gray. Oxford Clay ; Trance. 



BoucHARDiA, Davidson, 1849. 



Distr. — 2 sp. Brazil, 13 fathoms. B. tulipa, Blainv. (cxxxv, 

 45-47). 



Beak prominent, with a minute apical foramen ; deltidium 

 blended with the shell ; apophyses anchor-shaped, the septum 

 being furnished with two short lamellae. 



Platidea, Costa, 1852. 



Syn. — Morrisia, Davidson, 1852. 



Distr. — 3 sp. Mediterranean, W. Ind., Isle Bourbon. Fossil, 

 4 sp. Chalk — ; Europe. P. a7?omio't<ies, Scacchi (cxxxv, 50-52). 



Shell minute, conspicuously punctate; foramen large, en- 

 croaching equally on both valves ; hinge-area small, straight ; 

 loop not reflected, attached to a small forked process in the centre 

 of the valve. 



