NARRATIVE OF THE CRUISE. 
817 
has undergone profound alteration- from the long time it has been exposed to the hydro- 
chemical action of sea water. For analyses of these manganese nodules see Appendix Y. 
It appears then that Shark’s teeth, bone's of Cetaceans, cosmic metallic spherules and 
cliondres, highly altered volcanic -fragments, manganese nodules, and zeolites occur in 
greatest abundance in the abysmal red clay regions of the Central South Pacific, at that 
part of the earth’s surface farthest removed from continental land. AH these substances 
occur in the other deposits, but owing to the abundance of other materials present in the 
more rapidly forming deposits, they are covered up and masked, and the chance of obtain- 
ing them in the dredge is greatly reduced ; they are probably also in some degree pro- 
tected in these latter deposits, from the hydrochemical action of sea water. They are less 
abundant in the Radiolarian oozes than in the red clays, are still less so in Globigerina, 
Diatom, and Pteropod oozes, and have been dredged in only a few instances ’ in the terri- 
genous deposits which surround the shores of continents and islands. A few analyses of 
the bones, teeth, nodules, and deposits referred to above, are given in Appendix V., and 
fuller details will be given in the forthcoming Report on Deep-Sea Deposits. 
The Stomatopoda . — Professor W. K. Brooks of Baltimore, who is engaged in the 
preparation of a Report on the Stomatopoda collected by the Expedition, contributes the 
following note : — “ The general collection of adult specimens is of very little interest, as it 
contains nothing except well known species, but the surface collections of larvae are of great 
value, and they are sufficiently complete to furnish the material for a very exhaustive 
account of the metamorphoses, although it is impossible to give an intelligible description 
of them without illustrations. 
“ The group Stomatopoda is a very compact one, and the adults are almost exactly 
alike in general structure, differing from each other only in minor points. Contrary to 
the general rule, however, the larvae are much more different from each other than the 
adults. Instead of closely resembling each other at first and gradually changing as 
they approach maturity, the various species hatched from the egg as larvae differ from 
each other in many important features, and become more and more alike as they develop. 
“All the Stomatopod larvae are pelagic animals, and many of them have been 
collected by explorers, and have received distinct generic names, as adults. 
“ The Challenger surface collections contain hundreds of specimens of these larvae, at 
all stages of growth, and thus furnish the material for a thorough revision of this subject, 
showing that there are four quite distinct types of larval development, each of which is 
represented by several hundred specimens. 
“ I have at present been able to make a thorough study of only one of these, the 
Erichthus type. This is very fully represented in the collections, from a stage younger 
than the youngest figured by Claus and Faxon, up to a free-swimming animal with 
very nearly the structure of the adult. The youngest larva is a little Nauplius-like form, 
