fall periodically:  some of them sinking by day to escape the light, others rising only by day; others, again, appearing on the surface in spring, keeping deep down in winter.  Perhaps the majority of them are phosphorescent, sometimes shining by their own light, sometimes borrowing a glory from innumerable phosphorescent bacteria with which they are infested.  Nearly every class of the animal kingdom contributes members to this strange population.  The young forms of many fish, as for instance of conger, flying gurnards, and some flatfish, are pelagic and have colourless blood, and pale, transparent, gelatinous or cartilaginous skeletons.  The tadpole-like stages of the sea-squirts, which in adult life are to be found attached to rocks like weeds, drift about in the surface waters until their time comes for settling down in life.  Many other Ascidians pass their whole life as pelagic creatures.  A few molluscs, many kinds of worms, echinoderms, and their allies, crab and lobster-like creatures in innumerable different stages of development, are to be found there, while unnumbered polyps and jelly-fish are always present.  It would be difficult to imagine a better training for the naturalist than to spend years, as Huxley did, working at this varied assortment of living creatures.  Huxley declared that the difficulties of examining such flimsy creatures had been exaggerated.

“At least, with a good light and a good microscope, with the ship tolerably steady, I never failed in procuring all the information I required.  The great matter is to obtain a good successive supply of specimens, as the more delicate oceanic species are usually unfit for examination within a few hours after they are taken.”

Day after day, as the Rattlesnake crept from island to island, Huxley examined the animals brought up by his tow-net.  He made endless dissections, and gradually accumulated a large portfolio of drawings.  Much of the time he passed at Sydney was spent in libraries and museums, comparing his own observations with the recorded observations of earlier workers, and receiving from the combination of his own work and the work of others new ideas for his future investigations.  It was all entirely a labour of love; it lay outside the professional duties by which he made his living, and for a long time it seemed as if he was not even to gain reputation by the discoveries he knew himself to be making.  He writes in his autobiography: 

“During the four years of our absence, I sent home communication after communication to the ‘Linnaean’ Society, with the same result as that obtained by Noah when he sent the raven out of his ark.  Tired at last of hearing nothing about them, I determined to do or die, and in 1849 I drew up a more elaborate paper and forwarded it to the Royal Society.  This was my dove, if I had only known it; but owing to the movements of the ship I heard nothing of that either until