378 



NATURE 



\Feb. 20, 1890 



Melicerta. I coiled one of these round the wall of a deep cell, 

 and thus brought into the field of view, at once, more than a 

 hundred living MeliccrtcB of all ages and sizes, and all with 

 their wheels in vigorous action ; a display never to be for- 

 gotten. 



Such a tank, so stocked and managed, would probably enable 

 a patient and ingenious observer to decide several other points, 

 about which we are, at present, in ignorance : to say whether the 

 same individual always lays eggs of the same kind, or whether 

 it may lay now female eggs, now male, now ephippial eggs ; and 

 to say what determines the kind of egg that is to be laid ; 

 whether it is the age of the individual, or the supply of food, or 

 temperature, or sexual intercourse that is the potent cause. 



It would, too, hardly be possible for the male, to escape the 

 observation of a naturalist, who possessed a tank in which were 

 hundreds of Melicertce : and the male is as yet almost unknown. 



Judge Bedwell found in the tubes of the female, in winter, a 

 small Rotiferon resembling the supposed male, that I had seen 

 playing about M. tubularia ; only the former had a forked foot, 

 and sharp jaws that were at times protruded beyond the coronal 

 disc. Its frequent occurrence in the tubes in various stages of 

 development, and the nonchalance with which the female suf- 

 fered it to nibble at her ciliary wreath, inclined the observer to 

 conclude, that the animal was the long sought-for male. Un- 

 fortunately it was only observed when in motion, so that its 

 internal structure was not made out ; and the matter therefore 

 still rests in some doubt. 



No doubt it is a strong argument that the female would 

 probably suffer nothing but a male to take such liberties with 

 her ; but it would seem, from the following account, that it is 

 possible for such freedoms to be pushed too far, 



Mr. W. Dingwall, of Dundee, was on one occasion watching 

 a male Fioscule circling giddily round a female, and constantly 

 annoying her by swimming into her fully expanded coronal cup. 

 Again and again she darted back into her tube, only to find her 

 troublesome wooer blocking up her cup, and sadly interfering 

 with, what to a Fioscule is, the very serious business of eating — 

 for these animals will often eat more than their own bulk in a 

 few hours. It was clear at last that the lady would not tolerate 

 this persistent interference with her dinner ; for when — after 

 waiting, rather a longer time than usual, closed up in her 

 tube — she once more expanded, only to find him once more 

 in his old position, she lost all patience, and effectually 

 put an end to his absurdities, by giving one monstrous gulp, 

 and swallowing her lover. It will not surprise you to hear 

 that he did not agree with her, and that after a short time 

 she gave up all hope of digesting her mate, and shot him 

 out into the open again, along with the entire contents of her 

 crop. He fell a shapeless, motionless lump ; the two score and 

 ten minutes of a male Rotiferon's life cut short to five ; but, 

 strange to say, in a second or two, first one or two cilia gave a 

 flicker, then a dozen ; then its body began to unwrinkle and to 

 plump up ; and, at last, the whole corona gave a gay whirl, and 

 the male shot off as vigorous as ever, but no doubt thoroughly 

 cured of its first attachment. 



I have taken Melicerta riiigens, as an example of what yet 

 remains to be done, even with an animal which is as common in 

 a ditch, as a fly is in a house ; but almost every other Rotiferon 

 would have done equally well, for there is scarcely a single species, 

 whose life-histoiy has been thoroughly worked out. 



To me, natural history in many of its branches seems to 

 resemble a series of old, rich mines, that have been just scratched 

 at by our remote ancestors, and then deserted. Our predecessors 

 did their best with such feeble apparatus as they had ; it was not 

 much, perhaps, but it was wonderful that they did it at all with 

 no better appliances ; and it irks me to think that we, who are 

 equipped in a way which they could not even dream of, should 

 turn our backs on the treasures lying at our feet, and go off 

 prospecting in new spots, contented too often with a poor result, 

 merely because it is from a new quarter. 



Besides, the love of novelty is a force too valuable to be wasted 

 on a mere hunt for new species in any one group of animals, 

 especially unimportant ones. It should rather be used to make 

 us acquainted with the more striking forms of many groups. 

 Let us have no fear of the reproach of superficial knowledge ; 

 everyone's knowledge is superficial about almost everything ; 

 and even in the case of those few who have thoroughly mastered 

 some one subject, their knowledge of that must have been 

 superficial for a great portion of their time. Indeed, the taunt 

 is absurd. I can imagine that a superficial knowledge of law. 



or surgery, or navigation may bring a man into trouble ; but 

 what possible harm can it do himself, or anyone else, that he is 

 content with knowing five Rotifera instead of five hundred? 

 And yet if any naturalist were to study only Flosctilaria, 

 Philodina, Copeus, Brachionus, and Pedalion, it would give him 

 the greatest possible pleasure, as well as an excellent general 

 notion of the whole class. Let any tyro at the seaside watch the 

 ways and growth of a Plumularia, or of a rosy feather-star, his 

 knowledge of the groups to which they belong could certainly 

 not be dignified even with the term "superficial" — "linear" or 

 "punctiform" would be more appropriate; but the pleasure, 

 that he would derive from such a study, could not be gauged by 

 counting the number of animals that he had examined. It 

 would depend on the man himself; and might, I should readily 

 imagine, far exceed that derived by the study of a hundred times 

 the number of forms in books ; especially when such a study 

 had been undertaken, not from a natural delight in it, but from 

 some irrelevant reason, such as to support a theory, to criticize 

 an opponent, to earn a distinction, or to pass an examination. 



In truth that knowledge of any group of animals, which would 

 rightly be called superficial when contrasted with the knowledge 

 of an expert, is often sufficient to give us a satisfactory acquaintance 

 with the most interesting creatures in it ; to make us familiar 

 with processes of growth and reproduction too marvellous to be 

 imagined by the wildest fancy ; and to unfold to us the lives of 

 creatures who, while possessing bodily frames so unlike our own 

 that we are sometimes at a los; to explain the functions of their 

 parts, yet startle us by a display of emotions and mental 

 glimmerings, that raise a score of disquieting questions. 



Moreover, there is another excellent reason why we should not 

 confine our attention to one subject ; and that is, that even the 

 most ardent naturalist must weary at times of his special pursuit. 

 Variety is the very salt of life ; we all crave for it, and in 

 natural history, at all events, we can easily gratify the craving. If 

 we are tired of ponds and ditches, there are the rock-pools of our 

 south-western shores, and the surface of our autumn seas. A 

 root of oar-weed torn at random from a rocky ledge, an old 

 whelk shell from deep water, a rough stone from low-water mark, 

 the rubbish of the dredge, — each and all will afford us delightful 

 amusement. It is wonderful, too, what prizes lurk in humble 

 things, and how often these fall to beginners. The very first 

 time that I tried skimming the sea with a muslin net, I picked a 

 piece of green seaweed off the muslin, intending to throw it 

 away ; but, seeing a little brown spot on it, I dropped the weed 

 (not a square inch) into a bottle of sea-water, instead. At once 

 the brown speck started off and darted wildly round the bottle. 

 It was too small to be made out with the naked eye, but by the 

 time I had brought my lens to bear, it had vanished. I hunted 

 all over the bottle, and could see nothing, neither with the lens 

 nor without it. I was half inclined to throw away the water ; 

 but, as I was certain that I had seen something in it two minutes 

 before, I corked up the bottle and took it home. When I next 

 looked at it, there was the little brown creature flying about as 

 wildly as ever. I soon made out, now, that I had caught a very 

 tiny cephalopod — something like an octopus — and with a pipette 

 I fished it out, and dropped it into a glass cell. At least I 

 dropped the water from the pipette into the cell ; but the animal 

 itself had vanished again ; I could not see it either in the bottle 

 or the cell. I was not going to be tricked again ; so I pushed 

 the cell under the microscope, and there was my prize ; motion- 

 less, but for its panting ; and watching me, as it were, up the 

 microscope with its big blue-green eyes. It was almost colour- 

 less, and was dotted at wide intervals with very minute black 

 spots, set quincunx fashion — spots absolutely invisible to the 

 sharpest unaided sight. 



As I looked it began to blush — to blush faint orange, then 

 deeper orange, then orange-brown ; a patch of colour here, 

 another there, now running across one side of the body, now 

 fading away, again to appear on a tentacle ; till at last, as it re- 

 covered from its alarm, each black spot began to quiver with 

 rapid expansions and contractions, and then to spread out in ever 

 varying tints, till its wavering outlines had met the expansions 

 of its neighbouring spots ; and the little creature, regaining its 

 colour and its courage at the same moment, rush2d off once more 

 in a headlong course round the cell. 



I was the merest beginner when I saw this, but I had the good 

 luck, knowing nothing whatever about it, and never having given 

 the subject a thought, to see, with my own eyes, how effectually 

 cuttlefishes are protected by their loss of colour, and also to see 

 how the loss takes place. 



