TRIBE BRACHTOPODA. 310 



attached by the produced and pointed beak ; hinge-area triangular, 

 smooth; margins thickened and granulated internally; brachial 

 septum 3-lobed ; loop rudimentary, 4-lobed. T 5 T . Mediterranean. 



TEREBRATULA. 



Inequi valve, regular, attached by a pedicle or by the larger valve, 

 which latter has a more or less projecting perforated umbo ; hinge with 

 two teeth ; an internal skeleton. 



* Black ; surface not shagreened. 



T. Psittacea.* — Anomia P. Grin. 3348, from A. rostrum-psittaci, 

 Ch. f. 713.— P. p. 996.— W. t. 11, /. 27.— T. P. Lam. 12.— E. 

 t. 244, /. 3.— Sow. G.— Reeve, C. 8. t. 126,/. 5.— Sow. Th. 1, p. 342, 



t. 71,/. 78, 9, 80.— Hypothyris P. Br. Mol. 2, p. 346, t. 57, /. 1, 2, 3. 



Subglobose, acuminated dorsally, thin, blackish ; radiatingly 

 striated, strongly sinuated at the ventral edge. Upper valve acute 

 and recurved dorsally, deflected ventrally ; central sulcus broad and 

 indistinct ; cardinal area inconspicuous, rounded, the deltidia narrow, 

 uniting at the sides of the incomplete triangular perforation. Lower 

 valve ventricose, broader at the ventral margin, where the central 

 carination (elsewhere inconspicuous) becomes distinct : the two car- 

 dinal teeth recurved, and projecting to either side of the shell. 

 Inner margin quite entire. 1. N. Europe; Labrador ; Melville 

 Island ; very rarely in North Britain. 



T. Nigricans. Soiv. Th. 1, p. 342, t. 71, f. 81, 2. — Rynchonella 

 N. Davids. Z. P. 1852, t. 14,/. 30, 1. Rounded ventrally, pointed 

 dorsally, wider than long, rather thin, blackish, with about 25 rounded 

 radiating ribs ; marginal line straightish. Upper valve somewhat 

 triangular and rather depressed ; rounded ventrally, sloping dorsally ; 

 perforation large, square, not entire ; cardinal area large, flattish, the 

 sides rounded, deltidia narrow, uniting at the sides of the aperture. 

 Lower valve depressed, transversely ovate ; cardinal teeth as in the 

 last. Margin crenulated; apophysis consisting of 2 short curved 

 lamellas. f...f. N. Zealand. 



T. Grayii. — Rhynconella G. Woodiv. An. N. H. 1855, t. 10, 

 /. 16. Light horn-coloured, dull, trigonal, depressed, rounded at 

 the sides, truncated ventrally, smooth, but strongly plaited near the 

 margin with 4 central plaits and 3 or 4 on each side, the furrows 

 obscurely striated ; margin sinuated ventrally, and strongly toothed ; 

 perforation minute, completely tubular, -f-. Feejee Isles. 



