

XIV CLASSIFICATION. 



/^ 9. DoNAX : Hinge with a lateral tooth, generally remote, not 

 let into the opposite valve. 

 10. Venus: Hinge with generally three approximate divari- 

 cated teeth. 

 X) 11. Spondylus: Hinge with two teeth, separated by a small 

 hollow. 

 12. Chama: Hinge on one side, with an oblique obtuse 

 tooth inserted into a corresponding cavity. 

 M 13. Arca: Hinge with numerous penetrating teeth. 

 // 14. OsTREA : Hinge without teeth, but an ovate hollow. 

 yo \b. Anomia: Hinge without teeth, but generally a linear de- 

 pression on the rim, the beak of one valve curved over 

 the hinge. 

 /^. 16. Mytilus: Hinge without teeth, with a subulate depres- 

 sion. 

 // 17- Pinna : Hinge without teeth, valves united at one end, 

 and open at the other. 



HI. UNIVALVES. 



1 . With a regular Spire. 

 /, 18. Argonauta: Shell with one cell, spiral, involute. 



19. Nautilus: Shell with many chambers, communicating 

 by a tube. 



>? 20. CoNus: Aperture eflfuse, longitudinal, without teeth. 



^. 21. Cypr^a: Aperture effuse, linear, longitudinal, toothed 



on each side. 

 t/. 22. Bulla: Aperture rather contracted, and placed obliquely. 

 {T. 23. Voluta : Aperture eflfuse, the pillar plaited. 

 rr 34. BucciNUM : Apcrture with a small canal leaning to the 

 ^ right. 



^ 25. Stromeus : Aperture with a small canal leaning to the 



left. 

 y . 26. MuREX : Aperture with a small straight canal. 



/■ 



