EXPLANATION OF PLATES. 
445 
PLATE 128. 
FIGURE. PAGE, 
84, 85. Arca (Noetia) ponderosa, Say. 8. Carolina, . . 255 
86-88. Tridacna squamosa, Lam. Moluccas, : . 208 
89, 90. Tridacna (Hippopus) maculatus, Lam. E. Indies, 209 
91. 
99, 
Tridacna crocea, Lam. Philippines. a, the single ad- 
ductor muscle; p, pedal muscle, and pedal opening in 
mantle; f,the small grooved foot; b, byssus; ¢, labial 
tentacles: g, gills; 2, the broad pallial muscle; between 
g and 1 is the renal organ; m, the double mantle- 
margin; s, the siphonal Dorder ; zd, inhalent orifice; e, 
valvular excurrent orifice (An. Nat. Hist., 1855, P. 
NSO. es : 
Mytilus (Aulocomy a) decussatus, ‘Lam. Patagonia, 
93. Mytilus (Caloromya) afer, Gmelin. Algiers, 
94. Modiola barbata, Linn. Europe, : 
95. Modiola tulipa, ieee 4. Northern Europe, 
96. Modiola (Brachydontes) plicatula, Lam. U. 8., 
97. Lithodomus caudigerus, Lam. W. Indies, 
98. Lithodomus lithophaga, Linn. 34. Europe, 
99. Modiolaria impacta, Herm. N. Zealand, 
100. Dreissensia polymorpha, Pallas. Europe, 
1-3. Prasina Borbonica, Desh. Isle of Bourbon, 
4, Mytilus smaragdinus, Chemn. India, . 
PLATE 129. 
5. Arca (Granoarca) propatula, Conr. Mio.; Virginia, 
6. Arca (Trigonarca) triquetra, Conr. Cret.; N. Carolina, 
7. Megalomus Canadensis, Hall. Onondaga Salt Group, 
New York, 
9. Megambonia , aviculoidea, Hall 1, Helderberg Group, 
New York, . 
10. Pachymytilus petasus, vOrb. Jurassic ; France, 
11. Mytilus (Mytiloconcha) incurva, Conr. Miocene; v. 
States, ‘ 
12. Modiola (Adula) soleniformis, d’Orb. ‘Peru, 
13, 14. Orthonota contracta, (ORE bh. Sik» 1 S., 
15. Modiomorpha concentrica, Conr. Hamilton Group, 
New York, 
16. Lithodomus (Botula) splendida, Dunker. Australia, . 
17. Crenella decussata, Mont. Boreal Seas, 
18. Crenella (Nuculocardia) divaricata, d’Orb., A 
19. Crenella (Dacrydium) vitreum, Moller. Norway, 
20. Arcoperna filosa, Conr. Eocene; Mississippi, 
21. Myrinapelagica, Forbes. Cape of Good Hope, 
22. Dreissensia (Praxis) Sallei, Recluz. W. Indies, . 
23. Septifer Heberti, Desh., ° . 
