PLATE X. 
Fig. 1. ^lezorostral bone or beak of a Ziphioid whale (natural size). The whole bone is coated and impreg- 
nated with manganese. Station 286 ; 2335 fathoms. South Pacific. 
Fig. la. Section of the same (natural size), showing canals as in recent species. 
Fig. 15. Longitudinal vertical section of the same (magnified 50 diameters), showing the Haversian canals and 
lacunoe filled or partially filled with peroxide of manganese. 
Fig. 2. Portion of the brain-case of a Cetacean, much impregnated and covered by depositions of peroxide of 
manganese (natural size). Station 286 ; 2335 fathoms. South Pacific. 
Fig. 2a. Transverse vertical section of the same (magnified 40 diameters), shoAving that the bone is partially 
removed, depositions of manganese having taken place in the Haversian canals and lacunae. 
Fig. 3. Portion of very light spongy bone, probably a portion of the expanded wing of a superior maxilla, 
covered and impregnated with manganese (natural size). Station 286 ; 2335 fathoms. South 
Pacific. 
Fig. 4. Transverse section of Carcharodon tooth (natural size). The vaso-dentine is entirely removed from the 
interior, its place being occupied by depositions of manganese ; only the hard dentine remains. 
Station 286 ; 2335 fathoms. South Pacific. 
Fig. 4a. Portion of the dentine of the same (magnified 120 diameters); even the dental tubes are filled or 
jiartially filled with manganese depositions. 
Fig. 5. Longitudinal vertical section of Oxyrhina tooth (natural size), showing the centre filled with manganese 
dejwsitions. Station 286 ; 2335 fathoms. South Pacific. 
