328 TESTACEOUS MOLLUSCA. 



dorsal edge nearly straight ; interior with two small central diverging 

 branches which expand at their apices. |. S. Africa. 



T. Pisum. Lam. 3.— Sow. Th. 1, p. 345, t. 69, /. 37, 8, 9.— 

 Kkaussia P. Gray, Brack, p. 110. Transversely subovate, slightly 

 reddish ; valves nearly equal, with a few rather obsolete obtuse and 

 rounded radiating ridges ; margin slightly crenulated, not flexuous, 

 deeply sinuated ventrally : mesial ridge and furrow broad and rounded. 

 Upper valve slightly produced, very obtuse, with a large incomplete 

 perforation ; hinge-area small, linear ; deltidia small, nearly triangular. 

 Dorsal edge of the lower valve rather broad, nearly straight : apophysis 

 central, forked. T 5 r . Natal. 



T. Algoensis. Sow. Th. 1, p. 362, t. 71, f. 91, 92.— Kkaussia A. 

 Gray, Brack, p. 111. Suborbicular, slightly acuminated dorsally, 

 rather lobed ventrally, radiatingly striated ; mesial groove distinct, 

 roundish ; perforation large, incomplete. Inner edge of the upper 

 valve very minutely crenulated. 4x- Algoa Bay. Bower valve un- 

 knoivn. Not unlike the T. Natalensis of Krauss as delineated by 

 Kuster (vii. I, t. 2, h,f. 4, to 7). 



T. Lamarckiana. — Kkaussia L. Davids. Z. P. 1852, t. 14, 

 /. 22, 3. — Gray, Brack, p. Ill, /. 20. Suborbicular, striated with 

 fine bifurcated ridges, light yellow; hinge-area well defined, flat; 

 perforation large, incomplete ; deltidia small ; lower valve with a 

 mesial furrow ; apophysis central, bifurcated ; margins of the valves 

 thickened and spinulose within. \. Australia; N. Zecdand. 



T. Deshayesii. — T. Capensis. Adams (not Gm.), Sa?nar. p. 71, 

 t. 21,/. 4.— Kraussfa D. Davids. Z. P. 1852, 1. 14,/. 20, 1.— Gray, 

 Brack, p. 111. Rounded-subtrigonal, rather produced at the beak, 

 reddish brown, with about six red rays, thickish, radiatingly costated ; 

 perforation moderate, incomplete ; deltidia separate ; lower valve 

 depressed in the middle ; apophysis central, forked, -g-. Cape G. 

 Hope. 



T. Flavescens. Lam. — T. Dentata, Lam. 7. — T. Australis, 

 Quoy, Ast. t. 85,/ 1 to 5.— Sow. Th. 1, p. 349, t. 69, / 25 to 33.— 

 Waldheimia F. Gray, Brack, p. 58. — W. A. Woodw. t. 15./ 4. 

 Nearly oval, slightly acuminated dorsally, generally gibbous, some- 

 times slightly flattened, whitish, yellowish, or brownish ; valves 

 unequal, smooth, generally more or less (sometimes very obsoletely) 

 radiatingly grooved ; margin scarcely flexuous laterally, more or less 

 sinuated ventrally : mesial ridge and furrow broad, indistinct. Upper 

 valve obtuse, reflected ; perforation moderate, entire, round ; hinge- 

 area broad, rather indistinct, with rounded edges ; deltidia large, 

 united in the middle. Lower valve nearly circular, gibbous ; internal 

 appendage as in Dorsata, the upper loop being very large. Margin 

 generally toothed, teeth more or less numerous, large or small, 



