Terebratella.] BRACHIOPODA. 1075 



flexuous both laterally and in front ; beak incurved and truncated 

 by a large circular foramen, separated from the hinge-line by a delti- 

 dium in two pieces ; beak-ridges not very sharply denned. Surface 

 of valves radiately costellated ; ribs narrow, numerous, increasing 

 in number at various distances from the beak and umbo through 

 bifurcation and the interpolation of smaller and shorter riblets be- 

 tween the larger ones ; surface of valves crossed at various distances 

 by concentric lines of growth. In the interior of the dorsal valve the 

 cardinal process and hinge-plate are large and well denned ; the mesial 

 septum, of low elevation, extends to half or a little more of the length 

 of the valve. Loop large, doubly attached, the principal stems, before 

 attaining their greatest length, give off a flat oblique lamella, which 

 becomes fixed near the anterior extremity of the septum, the lamella 

 proceeding again and doubling in the shape of a loop. Colour 

 sanguineous or paler red, deepest in intensity at the lines of growth. 

 (Davidson.) 



Length. 4'65 mm. ; breadth, 48-5 mm. ; depth, 29-5 mm. 



Hob. Cook Strait to Stewart Island. 



Fossil in the Pliocene. 



2. Terebratella rubicunda, Sowerby, 1846. 



Tei'ebratella sanyuinea, Quoy and Gaimard, Voy. Astrol., Zool., iii, 1834, 

 556, pi. 85, f. 7, 8 ; not of Leach. T. rubicunda, Sow., P.Z.S., 1846, 92 ; 

 Thes. Conch., i, 1846, 351, pi. 70, f. 45-47 ; Button, M.IVZ.M., 177 ; 

 Davidson, Trans. Linn. Soc., iv, pt. ii, 1887, 84, pi. 15," f. 15-29. 

 T. inconspicua, Sow., P.Z.S., 1846, 93. Waltonia Valenciennesi, David- 

 son, A.M.N.H. (2), v, 1850, 475, pi. 15, f. 1. 



Shell somewhat orbicular or triangularly ovate, widest about the 

 middle, acuminated posteriorly ; dorsal valve moderately convex, 

 channelled along the middle by a broad concave sinus, commenc- 

 ing at the umbo and extending to the front, where it is produced a 

 little beyond the lateral curved margins of the valve ; marginal line 

 flexuous on the sides. Ventral valve deeper than the dorsal one, 

 with a convex well-defined mesial fold extending from the extremity 

 of the beak to the front ; beak incurved and truncated by a large 

 circular foramen, lying close to the urnbo or just separated from it 

 by 2 rather large deltidial plates that barely meet in the middle ; 

 beak-ridges sharply defined. Surface of valves either entirely smooth 

 or more rarely with small short rounded ribs commencing at a short 

 distance from the lateral and frontal margins of the valves ; surface 

 of valves crossed by concentric strongly marked lines of growth. 

 In the interior of the dorsal valve the hinge-plate is well defined, with 

 a cardinal process at its posterior extremity. A mesial septum of 

 small elevation proceeds from the base of the hinge-plate to about 

 one-half the length of the valve. Loop doubly attached, first to the 

 base of the hinge-plate, and then by a transverse lamella proceeding 

 from about the middle of the length of the principal lamella to the 

 anterior extremity of the septum, when, after again extending a little 



