(■)PLATE IV. 



Fig. I. Dental min iiiterstnatum Sowb. Spec. of Amsterdam Museum. 



Fig. 2. Dentaliuiii aprimun L. Spec. of Amsterdam Museum. 



Fig. 3 — 6. Dcntalium aprinuin var. incolor nov. var. St. 133 and 163. 



Fig. 7. Dentaliuui javanuiii Sowb. Spec. of Amsterdam Museum. 



Fig. 8 — 9. Dcntalium octangulatum Don. Spec. of Amsterdam Museum. 



Fig. 10 — II. Dentaliuin eburneum L. Spec. of Amsterdam Museum. 



Fig. 12. Dentaliuin eburneiun L. var. Spec. of Amsterdam Museum. 



Fig. 13. Dentaliuin eburneum L. var. {= D. novaehollandiae Chenu), a spec. 



from the Mus. d'Hist. Nat. of Paris. 



Fig. 14 — 16. Dentaliuin profundoruin E. A. Smith. St. %i and loi. 



Fig. 17 — 18. Dentaliuin Sibogae nov. spec. St. 159. 



Fig. 19. Dentaliuin Alartensi nov. spec, a much eroded specimen of St. 88. 



Fig. 20 — 21. Dentaliuin scinitraclieatum nov. spec. St. 248. 



Fig. 22. Dentaliuin tracheatum nov. spec. St. 208. 



Fig. 23. Dentaliuin transversostriatum. St. 212. 



i) The figures of Plate IV, V, VI are from photographs in natural size. 



