357 



Cuna concentrica, HecUey. 



Cinia concentrica, Hedley, Mem. Austr. Mus., vol iv., 1902, p. 

 315; Verco, Trans. Roy. Soc, S. Austr., vol. xxxi., p. 109, q.r. 



Cuna edentata, n. sp. PL xiv., f. 1 to 3. 



Shell ovate-trigonal, white, glossy* solid. Anterior and 

 posterior lateral borders nearly straight, the latter rather 

 shorter. Ventral border convex, slightly produced anteriorly. 

 A small prominent prodissoconch cap, about three-fourths of 

 a circle. Exterior has crowded concentric valid ribs, but no 

 radial sculpture. The right valve has a large central tri- 

 angular tooth, a minute anterior, at the extremity of the 

 long antero-lateral tooth, which is separated by a groove 

 from the margin, a marginal postero-lateral, with a minute 

 cardinal tooth above it, and above that a marginal socket 

 for the left posterior cardinal. The left valve has a large 

 anterior cardinal tooth, and a small posterior behind the 

 cartilage-pit, a long low postero-lateral tooth separated by a 

 groove from the margin, and a marginal antero-lateral. 



The inner ventral border is not dentated, whence the 

 name. 



Dim. — Antero-posterior diameter, VQ mm.; umbo-ven- 

 tral, r9 mm. 



Hab. — Gulf St. Vincent, dredged several. 



Diagnosis. — It is very like C. concentrica^ Hedley, but 

 the smooth internal ventral border distinguishes it. 



Type in Dr. Verco's collection. 



Cuna comma, n. sp. PI. xvii., f. 29 to 31. 



Shell solid, white, glossy, obliquely pyriform, with a 

 distinct three-quarter circle prodissoconch. Antero-lateral 

 border convex; postero-lateral concave below the umbo, then 

 straight, much shorter; ventral border convex produced an- 

 teriorly. Outer surface closely concentrically ribbed, no 

 radial sculpture. The right valve has a large central curved 

 cuneate tooth in front of the cartilage-pit, and a small pos- 

 terior tooth just below the umbo, with a littl-e socket out- 

 side and below it. The left valve has a large curved anterior 

 tooth, a lamina in front of the cartilage-pit, a small pos- 

 terior tooth behind the pit, and a small socket above and in 

 front of it. The antero-lateral in the right valve and the 

 postero-lateral in the left are separated from the margin by 

 a groove to receive the corresponding marginal lamina of the 

 other valve. The internal ventral border is not denticulated. 



Di7n. — Antero-posterior diameter, 2'6 mm.; umbo-ven- 

 fcral, 32 mm. 



Hah. — Dredged alive in 22 fathoms in Backstairs Pas- 

 sage, and in 20 fathoms off Newland Head; also in Gulf St. 



