PLATE LXXYI1I. 
I, 2. Cucullsea Glabra. (Smooth Cucullcea.) Rhomboidal, ventricose ; anterior angle obtuse ; 
hinge-area, with four sulci ; beaks incurved ; surface, with longitudinal striae, decussated by many 
lines of growth ; hinge-line, with fine striae ; teeth striated. 
3. C. Oviformis. {Egg-shaped Cucullcea.) Transversely oviform ; hinge-line curved; anterior 
side rounded; posterior side narrowed ; base and back arcuated ; surface smooth. 
4. C. Ovata. {Ovate Cucullcea.) Transversely ovate, convex; interior laminae longitudinal; 
sides l’ounded. Length, in. ; breadth, 1^ in. 
5. C. Pectinata. {Pectinated Cucullcea.) Transversely elongated; beaks obtuse ; anterior side 
rounded; back and base curved ; surface, with many striae, crossed by remote lines of growth. 
6. C. Triangularis. {Triangular Cucullcea.) Sub-triangular, cuneiform ; anterior side straight; 
beaks pointed; surface smooth, with a few, remote lines of growth. 
7. C. Costellata. {Small-ribbed Cucullcea.) Gibbose, transversely oblong; anterior lobe wing¬ 
shaped, ribbed, with intermediate striae and carinated division separating it from disc ; posterior side 
rounded, ribbed; beaks distant, sharp; surface, with longitudinal striae, decussated bylines of growth. 
8. 9. C. Antiqua. {Ancient Cucullcea.) Transversely ovate, smooth, convex ; internal lamina 
longitudinal ; umbones obtuse. Length, f to ^ in.; breadth, 4 to f in. 
10. C. Formosa. {Handsome Cucullcea.) 
II, 12. Pachymya Gigas. {Giant Pachymya.) Gibbose, ponderous ; anterior side small, 
rounded ; posterior side truncated ; ridge in both valves from umbones to margin ; umbones obtuse ; 
surface smooth, with imbricated laminae near basal margin. 
13. C. Reticulata. {Reticulated Cucullcea.) Transversely elongated ; inflated ; anterior side 
large, rounded ; posterior side truncated; beaks large, obtuse; surface, with longitudinal striae, crossed 
by transverse ridges, producing reticulated appearance. 
14. 16. C. Cancellata. {Cancellated Cucullcea.) V. Plate LXXVIL, Fig. 18. 
15. C. Cawdori. {Cawdor's Cucullcea.) Transversely oval, convex, smooth ; anterior side 
rounded, posterior side truncated; umbones acute, centi’al, whence rounded ridge to posterior angle, 
with oblique laminae within. 
17. C. Cylindrica. {Cylindrical Cucullcea.) Transversely elongated, cylindrical, ventricose; 
beaks prominent, close ; posterior side, with ridge from beaks to margin ; surface, with many, con¬ 
centric ridges. 
18. C. Concinna. {Neat Cucullcea.) Transversely elongated, inflated; beaks large; anterior 
side rounded, faintly ribbed; posterior side truncated, flattened, with ridge from beak to margin, and 
longitudinal striae; base curved. 
19. C. Elongata. {Elongated Cucullcea.) Elongated, sub-cylindrical ; anterior side pointed ; 
posterior side short; beaks small, incurved ; surface, with fine, longitudinal striae. 
20. C. Imperialis. {Imperial Cucullcea.) Transversely lengthened, inflated; anterior side 
short; beaks large, prominent, incurved, close ; upper portion of surface, with wide-set striae, crossed 
by concentric lines of growth ; basal line straight, with hollow near centre. 
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