Discourses - Biological and Geological Essays by Thomas Henry Huxley
page 82 of 318 (25%)
page 82 of 318 (25%)
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scattered, apparently irregularly, in the sarcode. We never have been
able to detect, in any of the large number of _Globigerinoe_ which we have examined, the least trace of pseudopodia, or any extension, in any form, of the sarcode beyond the shell. * * * * * "In specimens taken with the tow-net the spines are very usually absent; but that is probably on account of their extreme tenuity; they are broken off by the slightest touch. In fresh examples from the surface, the dots indicating the origin of the lost spines may almost always be made out with a high power. There are never spines on the _Globigerinoe_ from the bottom, even in the shallowest water." There can now be no doubt, therefore, that _Globigerinoe_ live at the top of the sea; but the question may still be raised whether they do not also live at the bottom. In favour of this view, it has been urged that the shells of the _Globigerinoe_ of the surface never possess such thick walls as those which are fouled at the bottom, but I confess that I doubt the accuracy of this statement. Again, the occurrence of minute _Globigerinoe_ in all stages of development, at the greatest depths, is brought forward as evidence that they live _in situ_. But considering the extent to which the surface organisms are devoured, without discrimination of young and old, by _Salpoe_ and the like, it is not wonderful that shells of all ages should be among the rejectamenta. Nor can the presence of the soft parts of the body in the shells which form the _Globigerina_ ooze, and the fact, if it be one, that animals living at the bottom use them as food, be considered as conclusive evidence that the _Globigerinoe_ live at the bottom. Such as die at the surface, and |
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