PLATE XCY. 
1. Pholas Gigantea. ( Gigantic Pholas.) Transversely elongated, cylindrical; anteriorly 
short, rounded; posteriorly elongated, angular below; surface, with radiating sulci and ribs; margin 
crenated. 
2. Pholadomya Nana. {Dwarf Pholadomya.) Transverselyeiongated; posteriorly straight; 
beaks large, obtuse; anteriorly rounded; surface, with concentric lines of growth, and a few, radiating 
sulci towards base in centre of valves; basal line straight. 
3. P. Obsoleta. {Obsolete Pholadomya.) Transversely elongated; beaks obtuse; posteriorly 
short, narrowed; surface, with concentric sulci and four, radiating sulci from beaks to basal line. 
4. P. Ambigua. {Ambiguous Pholadomya.) Transversely elongated, gibbose, recurved; gaping 
anteriorly; surface, with several, divergent sulci. 
5. P. Compressa. {Compressed Pholadomya.) Transversely elongated, cordiform, compressed; 
beaks large, prominent, approximating; surface, with six, large, radiating ribs. 
6. P. Obtusa. {Obtuse Pholadomya.) Gibbose, transversely obovate, recurved; anteriorly 
obtuse, plain, with seven to ten, longitudinal, tuberculated ridges. 
7. P. Clllieata. ( Wedge-shaped Pholadomya.) Transversely obovate, cordiform, gibbose; 
anteriorly produced; posteriorly very short, with longitudinal keel and several narrow ridges, con¬ 
centrically undulated. 
8. P. Producta. {Produced Pholadomya.) Gibbose, transversely oblong; surface, with six or 
seven, longitudinal ridges; anteriorly produced, plain; beaks prominent. 
9. P. Lirata. {Ridged Pholadomya.) Gibbose, transversely oblong; posteriorly convex, with 
large ridge and two or three, tuberculated ridges; surface, with nine or ten, tuberculated ridges. 
10. P. Deltoidea. {Lurking Pholadomya.) Gibbose, obtusely triangular, with eight or nine, 
longitudinal, tuberculated ridges; anteriorly pointed; beaks prominent. 
11. P. Phillipsii. {Phillips’s Pholadomya.) Transversely oval, inflated ; beaks produced, in¬ 
curved ; posteriorly short, with long, longitudinal ribs from beaks to basal line, producing scalloped 
aspect; anterior to these, two radiating sulci; anteriorly rounded, contracted below. 
12. P. Simplex. {Simple Pholadomya.) Obliquely oblong-ovate; with ridge from beak to 
base; surface smooth, with concentric lines of growth, forming acute angle on ridge; beaks produced. 
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