PLATE 16 



1. Astarte undata Gould. p. 43. 



2. Thyasira goiildii Philippl. p. 45. 



3. Solemya veliom Say. p. 25. 



4. Astarte quadrans Gould. 6 mm. p. 43. 



5. Cardium plnnulatum Conrad. 12 mm. p. 49. 



6. Dlvaricella dentata Wood. p. 47. 



7. Astarte castanea Say. 23 mm. p. 43. 



8. Laevicardium mortoni Conrad, animal extended, p. 50. 



9. Venerlcardia borealis Conrad, typical form. p. 44. 



10. Venerlcardia borealis novangliae Morse, p. 44. 



11. Crassinella mactracea Linsey; much enlarged, p. 43. 



12. Thyasira obesus Verrillj much enlarged, p. 45. 



13. Crassinella mactracea Linsey. 6 mm. p. 43. 



14. Lucina filosa Stimpson. p. 46. 



