•27C 
THE VOYAGE OF H.M.S. CHALLENGER. 
brittle. The great majority of the large cancellated bones of the whales appear to have 
been wholly removed from the deposits through the chemical action of the sea-water. 
With respect to the distribution of the earbones and fragments of other Cetacean 
bones, it will be observed that no specimens were obtained north of the equator either in 
the Atlantic or Pacific. From terrigenous deposits only one earbone was dredged, viz., at 
Station 299, 21 GO fathoms, over 100 miles from the South American coast, where the deposit 
was a Blue Mud. These Cetacean bones are also rare in Globigerina Ooze, being obtained 
in only three instances, viz., one bulla at Station 131, 2275 fathoms, in the South Atlantic 
(the only Cetacean bone procured in the Atlantic); a fragment at Station 143, 1900 fathoms, 
100 miles south-east of the Cape of Good Hope; and another fragment at Station 293, 
2025 fathoms, in the South Pacific. With the above exceptions all the bones of Cetaceans 
j)rocured during the Challenger Expedition were dredged from Bed Clays and Eadiolarian 
Oozes, and these are all situated in the Central South Pacific, excepting Station 160, 2600 
fathoms, in the Southern Indian Ocean, 500 miles southwest of Australia. 
The preservation of the earbones and fragments of beaks of Ziphioid whales is to be 
accounted for by the great density of these portions of the skeleton, and the consequent 
small amount of surface presented to the action of sea-water when compared with the 
cancellated bones. Professor Sir William Turner points out that he could not identify 
any of the bones as belonging to the great Sperm Whale {Physeter macrocephalus), 
although the track of the Challenger, where these hauls of Cetacean bones were made, was 
through the part of the Pacific frequented by that huge Cetacean. 
The distribution of the sharks’ teeth in the deposits is similar to that of the bones of 
Cetaceans, although they were dredged more frequently. They are most abundant in 
the red clay areas far removed from land, and especially in those of the Central South 
Pacific ; they were less frequently taken in the organic oozes of the deep sea, and only 
in one or two instances in the terrigenous deposits surrounding continental or other 
land. It seems undoubted that many of the teeth of sharks and the bones of the 
Ziphioid whales belong to Tertiary and extinct species. 
In the foregoing paragraphs we have indicated the various kinds of organic structures 
of a calcareous nature which enter into the composition of marine deposits, and we have 
to some extent pointed out their bathymetrical and geographical distribution. Those 
structures, like the bones of fish and marine mammals, or even the exoskeletons of Crus- 
tacea, wliich are very areolar in structure, and contain a large quantity of phosphate of lime 
a.ssociatcd witli much albuminoid matter, appear to be able to resist the solvent action 
of sea-water only for a relatively short time, so that tliey disaj)pear from marine deposits 
much more rapidly than the bones with a denser structure. The otoliths of fish, the 
hard dentine of sharks’ teeth, and the dense earbones and beaks of certain whales, resist 
for a longer time the solvent ar^tion of the sea- water, and may therefore accumulate and 
