1883.] MR. G. B. SOWERBY ON NEW SPECIES OF SHELLS. 31 



rather thin, inequilateral, umbones posterior ; both valves faintly 

 irregularly wrinkled with concentric striae ; dorsal margin posteriorly 

 sloping to an angle ; anterior side arched, and obliquely sloping to- 

 vyards the ventral margin; posterior obliquely truncated; ventral 

 margin very slightly arched ; umbonal ridge obtusely angulate ; 

 hiuge with cartilage-processes rather small. 



Long. 3.5, alt. 26, lat. 13 mill. 



Hab. Port Jackson (Brazier). 



Another interesting species of the genus Thrncia from the same 

 locality as the one described by Mr. Angus in the 'Proceedings' of 

 1869, and discovered by the same persevering and intelligent col- 

 lector. 



Tellina BRAziERi, sp. u, (Plate VIL fig. 2.) 



Shell transversely ovate, nearly equilateral, moderately thin, dull 

 yellowish white, without markings ; concentrically laminated, laminae 

 very fine and thread-like ; umbones acute, rather prominent, approxi- 

 mate ; anterior side rounded, posterior truncated ; anterior dorsal 

 margin incurved, posterior sloping in a straight line to form an angle 

 with the side ; ventral margin arcuate ; dorsal area slightly depressed ; 

 ligament long and narrow. 



Long. 8, alt. 7, lat. 2 mill. 



Hab. Port Jackson {Brazier). 



A remarkable little species having the form and external appear- 

 ance of an Amjihidesma. 



Tellina modesta, sp. n. (Plate VII. fig. 1.) 



Shell transversely ovate, rather inequilateral, compressed, thin, 

 white, shining; concentrically very finely striated; anterior side 

 rounded, posterior slightly flexuous ; dorsal margins sloping ; ven- 

 tral margin strongly arcuate ; umbones small, approximate ; dorsal 

 area very slightly impressed ; ligament moderate. 



Long. 12, alt. 9, lat. 3 mill. 



Hab. Port Jackson (Brazier). 



A delicate shining white shell of very simple character. 



Pectuncxjlus robustus, sp. n. (Plate VII. fig. 4.) 



Shell suborbicular, solid, subequilateral, very pale yellowish brown, 

 here and there sparingly banded and spotted with darker brown ; 

 anterior side rounded, posterior angulated, slightly incurved and de- 

 pressed above the angle ; dorsal margin straight ; ligamentary area 

 narrow ; umbones rather acute ; valves radiately ribbed (ribs pro- 

 minent, rounded, close-set, about 23 in number, much narrower 

 above the angle), concentrically striated ; striae thread-like, crossing 

 ribs and interstices. 



Long. 40, alt. 37, lat. 22 mill. 



Hab. ? 



A very distinct and characteristic species. 



