PLATE XCIII. 
1. Mya Truncata. ( Truncated Mya.) Sub-ovate; posteriorly truncated, gaping; hinge-line 
straight; basal line parallel to back; surface, with many, concentric wrinkles. 
2, 3. Thracia Oblata. ( Brought-up Thracia.) Transversely oval, compressed; sides obtuse, 
bent; beaks prominent; surface small; with small keel near posterior side; pallial impression, with 
deep sinus. 
4. M. Lata. ( Broad Mya.) Ovate, compressed; anteriorly acuminated, truncated, with arcuated 
margin, gaping; beaks produced, acute ; surface smooth, with a few undulations ; tooth large. 
5. T. Depressa. ( Depressed Thracia.) Obovate, compressed, gaping; anteriorly short; hinge¬ 
line straight, depressed; ligament external, short; beaks prominent, incurved; surface smooth, with 
many, wavy lines of growth; shell thin. 
6. M. Calciformis. ( Shoe-shaped Mya.) Transversely lengthened, short, rounded at both 
ends; posteriorly narrowed; with slight inflection towards centre at base; surface smooth. 
7. 8, 9. T. Dllbia. ( Dubious Thracia.) Transversely ovate; beaks approximate; with flexure 
from beaks to base; surface smooth. 
10. Solemya Primseva. (Primaeval Solemya.) Transversely oblong-oval, compressed, rounded; 
beaks depressed; surface, with widish, radiating stria?. 
11,12. Panopsea Rotundata. (Hounded Panopcea.) Orbicular, gibbose; beaks obtuse, central, 
approximate; anteriorly rounded; posterior side, with curved ridge from beak to margin, above 
which obliquely truncated; basal line arcuated. 
13. P. Gibbosa. (Gibbous Panopcea.) Gibbose, transversely elongated; anteriorly wide, 
recurved, truncated, gaping; beaks incurved, pointed. 
14, 15. P. Intermedia. (Intermediate Panopcea.) Ovate, depressed, inequilateral, thin, longi¬ 
tudinally ribbed; hinge, with one, cardinal tooth close to pit of hinge. 
16. P. Elongata. (Elongated Panopcea.) Transverselyeiongated; beaks sub-central, obtuse; 
ends rounded; with oblique ridge from beak to margin posteriorly; cardinal margin straight; surface, 
with concentric wrinkles. 
17,18,19. P. Norwegica. (Norwegian Panopcea.) Transversely oblong, compressed, thick; 
posteriorly truncated above, rounded below; with two longitudinal sulci from beak to margins, 
dividing valve into three parts; back and basal lines parallel; surface, with concentric wrinkles; 
muscular impressions deep; pallial impressions large. 
20. Solemya Ovalis. (Oval Solemya.) 
21. Nseara Dispar. (Differing Nceara.) Transversely and acutely oval, thin, biangulated in 
front, acuminated into beak-like elongation; right valve, with concentric sulci; left valve smooth. 
22. P. Oblata. (Raised Panopcea.) Sub-triangular, gibbose, gaping; anteriorly attenuated ; 
beaks prominent, incurved; surface, with transverse sulci. 
( H2 ) 
