BY C. HEDLEY. 475 



about twenty-two radial ribs parted by narrow though deep 

 grooves, and densely packed with compressed beads which 

 enlarge gradually with the growth of the shell. It is the chief 

 peculiarity of the species that these ribs do not diverge from the 

 umbo, but centre at a point in space considerably beyond the 

 shell. Lunule and impressed dorsal area are unsculptured. 

 About eighteen small interlocking tubercles on the inner ventral 

 margin. Height 1*7 mm.; length 1-65 mm.; depth of conjoined 

 valves 1 mm. 



An abundant species in 17-20 fathoms. 



Condylocardia porrecta, n.sp. 

 (Plate xxxviii., fig.24.) 



Shell larger than is usual in the genus, solid, rhombic-oblong, 

 inequilateral, anterior end short. Colour white. Sculpture : 

 about fourteen low broad radial ribs, parted by narrow grooves and 

 crossed by delicate growth-lines. Anterior and posterior dorsal 

 areas smooth. Prodissoconch large, with projecting rim, and 

 containing a second inner shield upon the umbo. From within 

 the ribs are visible because more opaque than their interstices; 

 their ends strongly denticulate the inner margins of the valves. 

 Height 1*9 mm.; length 2-5 mm.; depth of conjoined valves 

 1*3 mm. 



A few examples dredged from 17-20 fathoms. 



Condylocardia tripoliata, n.sp. 



(Plate xxxvii., figs.20, 21, 22, 23.) 

 Shell solid, inflated, oblique, much higher than long, triangularly 

 ovate, with a flattened anterior area like a lunule. Surface 

 glistening in the light. Colour pale ochre, passing into pearly 

 white on the umbo. There is no radial sculpture; about twenty 

 strong corrugations undulate the middle of the valve, diminish 

 posteriorly, and cease anteriorly. Prodissoconch large, with 

 expanded upturned margin projecting over the main shell. An 

 umbonal boss bears a trefoil scar, and is surrounded by two con- 

 centric ridges. Hinge massive; left valve with an anterior and 



