882 rnncKKiuxGS OF THE NATIONAL MUSEUM. VOL.XX. 



those which precede them and a little different in form. Above the 

 teeth there is a distinct and rather deep submarginal groove for the 

 ligament which extends continuously both in front of, and behind the 

 beaks. Behind the beaks there is a distinct rounded ridge running 

 outside of, and parallel with the ligamental groove and terminating at 

 the distal end of the row of teeth. Pallial line entire; 110 siphon; anal 

 opening separated, surrounded by about twelve unequal papilla 1 ; else- 

 where the open mantle edge is nearly plaiu; foot large with a creuate 

 disk. 



Epidermis pale yellowish brown; interior glossy bluish white without 

 pearly luster. 



Length, 8 mm.; height, 6 mm.; thickness, about 4.5 mm. 



A small specimen (3 mm. long, 2.5 mm. high) from station 2714, is 

 doubtfully referred to this species. Externally it is covered with very 

 fine regular, concentric, raised lines and grooves, agreeing well with 

 the corresponding umbonal portion of the type. The epidermis is thin, 

 pale straw color. The outline is also similar but the posterior half of 

 the shell is relatively a little broader, owing to a slight expansion of 

 the postero- ventral margin. The beaks appear to be relatively less 

 prominent. The external ligament is well developed both sides of the 

 beaks, and is slightly thickened just under them, and tills a very slight 

 notch in the edge of the hinge margin above the teeth. The hinge- 

 plate is relatively broad and strong, especially anteriorly. There are 

 thirteen posterior and nine anterior teeth, the two series separated by 

 a small edentulous space. Some of the distal teeth in the anterior 

 series are unusually large and stout and exceed any of those in the 

 posterior series. The pallial line is distinct and entire. 



One live specimen (station 25t!G), K lat. 37 23', W. long. G3 8', in 

 2,620 fathoms, 1885. One, very young, live specimen (station 2714), N. 

 lat. 38 22', W. long. 70 17' 30", in 1,825 fathoms, 1880. 



This species is remarkable for its thick, linn shell, regular ovate 

 form, and very even, concentric sculpture. In form and general 

 appearance it resembles some species of Callista. 



TINDARIA LATA, new species. 



Shell rather thick, somewhat compressed, broad-ovate, equilateral, 

 narrowest in front of the beaks, the posterior end somewhat produced 

 and very broad. Umbos only slightly prominent. Beaks small, rather 

 acute, turned directly forward and closely appressed to the margin. 

 Kolunule nor escutcheon. The autero-dorsal margin is nearly straight 

 and slopes but little, but becomes a little convex and passes insensibly 

 into the evenly rounded curvature of the anterior end; the ventral 

 margin is very evenly and broadly rounded but the curve recedes as it 

 passes backward so that the highest part of the shell is distinctly 

 behind the middle; the posterior end is very evenly and broadly 

 rounded without any augulation; the postero-dorsal margin is consid- 



