cost and trouble from England, and not procurable save by rare chance any nearer here) from the aggressions of their fellow prisoners; and this is a constant source of difficulty for me, for large as this establishment is, and many as are the separate tanks, they are not numerous enough to contain all the kinds of creatures which can be got, without most of them meeting with enemies of some sortactive or passive-in the same receptacles; and yet all the animals, whether friendly or unfriendly to each P.S.-Feb. 1st. The mullet still continue to improve and grow, and all have nearly recovered their lost tails. Their appetites, too, have got to be more universal, and they will freely eat the flesh of the oyster or mussel. But they will leave anything for crustacea flesh.-W. A. L. NOTE.-April 20th. The mullet have grown much lately, and they take a greater variety of food than at first. Only one has died here. I have at other, are of interest to the public. For example, length got Aspidophorus to feed on living Mysis sometimes when food is given to the mullets, and long before they are aware of its presence on the floor of the tank, an enormous black goby will rush out of its hiding-place, and, while its colours are rapidly changing from inky blackness to pale grey, and vice versá, according to the wont of many fishes when excited, it will seize hold of the food, and if too large to be carried away bodily, will shake it like a terrier dog, and hover about it for a long time, so that the mullets get no chance; and indeed they would have but a sorry life if it were not that the black gobies are bottom fish and the mullet are not. Then, at nightfall, the rocklings, which hide nearly all day, issue forth, and are quite as tyrannical as the gobies. Therefore the only plan I can adopt is first to feed these antagonistic fishes to satiety at proper times, such as late at night, on mussels and chameleon, a small shrimp-like crustacean of rather less than an inch long, found abundantly in the Baltic Sea at Kiel, and besides being thus useful for breeding purposes, it is itself an interesting aquarium object. Unlike the shrimp, which usually burrows out of sight in the sand, taking now and then a flight in the water above, and also unlike the prawn, which passes much of its time in clinging, partially hidden, to rocks, Mysis is ever perpendicularly suspended in mid-water, and when some hundreds are present in some tanks, and thousands in others, the effect produced by their being thus all quite parallel to each other is a very singular one.-W. A. L. other kinds of food which the mullets do not much HA care for. The blennies tease the mullets but do not W. ALFORD LLOYD. DESMIDIACEÆ. AVING dealt with the most common genera of desmids, we proceed to notice a few others which, though not so plentiful as those enumerated, are yet too frequently met with to be excluded from our chapter. We have made great efforts to obtain the specimens necessary for the purpose, in the neighbourhoods of Keston (Kent), Esher, Wimbledon Common, and Streatham. The bog at Keston yielded our most beautiful examples, and our richest collection. The other localities produced more limited supplies, and, with some exceptions, the specimens were not so bright in colour. After allowing each gathering to settle, the superfluous clear water was poured off, and the residue of mud, &c., was placed in the light, to enable the desmids to extricate themselves under its potent influence. This they did very readily, congregating in tiny green clusters on the top of the sediment. Any one of these clusters, removed to a glass slide and examined, presented a most beautiful appear ance. Closteria appear to be more generally distributed than any other Desmidiacea. We found many kinds in all our gatherings: occasionally, self-division was seen, and one or two examples of conjugation occurred with a species having attenuated ends (probably C. setaceum or C. rostratum), which we gathered at Streatham (Telford Park). The genera Penium and Docidium bear a close resemblance to Closterium, both in outward form and in possessing, save in a few cases, terminal cells containing active granules, like the genus referred to. Penium, of which there are, according to clavatum) exhibited the swarming motion so well, that we endeavour to give a representation of it. At certain points the moving granules were collected in greater numbers than elsewhere. Fig. 136. Penium digitus x 250. Pritchard, ten species, vary much in size and appearance. They are all straight, and mostly stouter at the middle than at the ends; that is to say, they are cylindrical, but taper more or less towards the Fig. 139.-a. Docidium clavatum x 40. b. End The filamentous Desmidiacea are not of such common occurrence in Great Britain; having their head-quarters in other countries. Still, however, several species are to be met with; and among the greatest favourites is Didymoprium. This fortunately is widely spread, but it has not as yet come in our way. The numerous joints or segments are somewhat barrel-shaped. There are two species. We found at Keston, the pretty Hyalotheca dissiliens in considerable quantity. It is enclosed Fig. 138.-a. Penium Navicula x 250. b. End of P. interruptum is the most beautiful, but we have not yet found a specimen, though it appears to be widely distributed both in Europe and America. Docidium, of which about twelve species are recognized, differs from the last in having a constriction, more or less conspicuous, at the centre of the frond, which is elongated, and terminates in abruptly truncate ends, where there is always (?) a rounded clear space with active granules. Among those which we examined, we found one bearing a strong likeness to the figure given in Pritchard and elsewhere of D. truncatum; but in many examples an appearance (perhaps deceptive) of cilia or setæ was conspicuous under the microscope. We found this kind at West End, near Esher. Another (D. Fig. 140. Hyalotheca dissiliens. in a thick gelatinous sheath, serving to keep the joints together; for they are very fragile, and hence pieces of greater or less length often occur. There are two species; one of them H. dubia, found in Germany, is said to be without the mucous sheath. Pritchard doubts this. Passing over many interesting genera of filamentous desmids, the end view of all of which is peculiar, from the arrangement of the endochrome in a three-rayed, four-rayed, circular or spiral manner, we come to an exceedingly pretty form, Spirotania. It is enclosed in a somewhat egg-shaped mass of mucus, and the chlorophyll is arranged in one or more spiral bands. The sheath in this genus and many others is difficult to be seen on account of its transparency. Colouring the water is recommended as a good plan for rendering it more plainly visible. Fig. 145. Staurastum alternans x 250.-a. Side still more fantastic. The figures representing both the end and front views of the species we saw, will give a better notion of them than a verbal description. They are all minute, and thus liable to be over. looked if a quarter-inch objective be not employed in the search. We found one curious example of self-division. The result of conjugation in Desmidiaceæ, viz., a Sporangium, is generally spherical. Its surface is very often studded with eminences or forked spines. Mr. Ralfs, speaking of the development of these curious bodies, says, "the Sporangia I consider capsules, and this view seems to be confirmed by the experience of Mr. Jenner, who states that the covering of the Sporangium swells, and a mucus is secreted in which minute fronds appear, and by their increase at length rupture the attenuated covering; " then Brawn, also quoted by Pritchard, writes respecting the same obscure subject, "certain early conditions observed in Closterium and Euastrum, namely, families of unusually small indi a Fig. 143. Staurastrum gracile (?) × 250.-a. End clouds which the slightest touch is sufficient to disperse through the water. For this reason it was Fig. 146. Euastrum didelta. viduals enclosed in transparent colourless vesicles, render it even probable that in certain genera of Desmidiea, a number of individuals are produced from one spore by a formation of transitory generations occurring already within the spore. The enclosing vesicle is probably the dissolved and swollen-up internal cell-coat of the spore, which holds the young individuals combined for some time after the outer coat of the spore has been thrown off;" and Mrs. Thomas also gives her opinion that "the Sporangium is the winter casing of a large number of young plants which escape from it by rapidly knocking against the walls, when these have been loosened by spring warmth, or which grow up as the walls gradually decay in the midst of slimy gelatinous masses." In our own examinations we found the minute fronds exceedingly numerous, and to our surprise, under very high powers we observed the swarming motion of the granules of Endochrome (to which reference has been made), in many of those which we were disposed from their shape to consider as immature; leaving us in doubt whether the phenomenon so frequently seen is a symptom of growth, reproduction or decay. Curious bodies closely resembling Sporangia, frequently occurring in flints, have puzzled their discoverers much. Their similarity to recent forms inclines to the belief, almost amounting to a certainty, that in them the Desmidiacea of past eras have left their only traces, while the fact that Desmids of modern times are wholly of fresh-water habit, whereas flints are admitted on all sides to be the remains of marine sponges, militates in some degree against the supposition. These bodies are called Xanthidia, and are thus spoken of by Mr. Ralfs, who appears to have no doubts as to their nature. "The fossil forms vary like recent Sporangia in being smooth, bristly, or furnished with spines, which in some are simple, and in others branched at the extremity." It may be well to notice the advantages we gained in the examination of our Desmids by means of Messrs. Powell and Lealand's new binocular, as applied to a one-twelfth object-glass. The circulatory currents in and around them, under these conditions, as may be imagined, were rendered far more distinct than before, and thus new beauties in these minute organisms were displayed. In one fragment of Hyalotheca, the continuous current in the water, rendered apparent by the particles carried along with it, gave rise to the suspicion of cilia. But the motion may have had some other cause, such as the struggles to get free of a cramped up Cypris, on a comparatively distant part of the slide; and we place very little faith in the existence of cilia in desmids. When speaking of the Polycistina in SCIENCE GOSSIP, Vol. I., Mrs. Bury compares them to the "Toilette-service of Titania, with all her essencebottles and trinkets." Following up the notion, may * We may infer from this lady's observations that conjugation is best witnessed in summer and autumn. we also inquire respecting the fairy bijouterie of the said queen, if she ever commissions her sprites to collect from the bottom of the rills and brooks of earth, gems wherewith to deck her royal brow in the moon-lit glade where she holds court? Disdaining rubies and emeralds, as suited only to mortals' wear, do her zealous servants supply the place of the latter gems with choice desmids, than which no emerald can be more beautiful; and of the former by the eyes of Cypris and Cyclops, than which no ruby can display more living fire? Disbelieving, let us hear from the elves' own mouths their duties. "Over hill, over dale, Thorough bush, thorough briar, Thorough flood, thorough fire, I do wander everywhere, Doubts however still arise, but there is another alternative to satisfy our curiosity. Gentle Reader, announce where she is to be found, and "I'll meet by moonlight, proud Titania." J. M'INTIRE. THE LARGE WOOD ANT. DURING a warm spring, a workman dispersed a nest of the large wood ant (Formica Herculanea). This species is of a dark chesnut colour. It is chiefly found in woods where fir-trees predominate. There they build large conical shaped nests, composed principally of fir-leaves. The male ant is said to be winged; yet, during the many years I had the opportunity of daily observing these ants, I never saw one of them with wings. This dispersion occurred two fields distant from the house, situated eastward from the nest. The country people say these ants always travel east, that is towards the rising sun. They took possession of our entrance door, and made their first habitation in the space between the woodwork and the lead over the porch. There they increased rapidly, and amused rather than annoyed us. Indeed, we passed much time in observing these industrious little people. Whether-according to the prediction of Solomon-we were wiser for our studies I must leave. We were not long in discovering that our new visitors were superior to mere plodders for their daily bread, and that they possessed more intelligence than we thought possible. To our surprise we were never stung by them, even when unintentionally touched rather rudely, or when they strayed on our persons. In fact, they appeared to consider us friends, residing under the same roof. I state this now, because the reverse took place in the sequel. The way these ants carry food, sticks, &c., to their nest, is well known; but I think few persons are aware that these ever busy ants occasionally allow themselves a holiday, not individually, but the whole community enjoy a day of festival. A fine one was chosen, when all were abroad without employment or work. They passed to and fro, greeting each other evidently in a kindly manner: they touched with their antennæ, like one shaking hands, remaining a few moments together, as if in friendly conversation, then passing on, the same ceremony was performed towards other fellow citizens. These proceedings continued until evening. On the following morning they were all at work again. We often threw our lowly companions crumbs of bread, pieces of meat, or grains of wheat. It was curious to see how quickly these gifts were carried away. If part of the offering proved too large for the strength of a single ant to remove, then as many as the load required would instantly offer aid to their overburdened friends, although previously busily engaged themselves. Their readiness to help their neighbours I have admired again and again. Some naturalists attribute this to the supposition that their possessions are in common. If they really are, it is an admirable proof of their willingness to do their duty as citizens of a commonwealth. Well would it be if men, in their transactions with each other, were as disinterested as the insignificant ant. Milton writes: "The parsimonious emmet, provident of future : Pattern of just equality perhaps Of commonality." My observation led me to conclude these ants are not provident for the future beyond securing a convenient and warm dwelling, while in a state of torpidity. Without this forethought the winter frosts would destroy them. The food so industriously collected during summer is, I think, only for their young, and their own immediate eating. When some of my ants were disinterred during winter, no stores of any kind were discovered. The ants were simply packed together in little heaps, as if waiting for the sun's heat to reanimate them. Once, and only once, during many years, I witnessed a battle between these creatures, generally so peaceful. It was fought on the wall of the house; so furious was the struggling and fighting between the opponents, that there could be no doubt of their deadly intentions. The contest lasted the whole day, and the ground beneath was covered with the slain. The following morning the victors were actively engaged in removing the dead. This task performed, their usual occupations were resumed, as if nothing extraordinary had previously occurred. I have seen these determined insects attack a large carthworm, probably a quarter of a yard long, and its defenceless body so thickly covered with ants that it resembled a piece of dark cord. The poor worm was not quickly killed, the whole mass occasionally moved as the victim writhed in its agony. More extraordinary was an attack made by them upon a large unshelled snail, or slug. I was attracted to the spot by the strange bubbling noise the snail made in its defence. This was to throw out its slime all over its body so profusely as to cover it with foam; but to no purpose: the persevering ants vanquished the snail. After a time the ants increased greatly. They became so bold as to enter our sitting-rooms, and chambers. Of course they were troublesome, and the order was reluctantly given for their destruction. Many methods were tried unsuccessfully. They had got so completely into the foundation of the house, that it was impossible to get at them during the winter, when they are in a torpid state. Therefore the tedious and painful one was resorted to of killing them singly. After the slaughter had commenced, it was sad to see the distress of the poor insects, when they discovered their friends had become their foes. Their confiding manner was gone. When they caught sight of us-which they did quicklythey stopt, stood partly erect, and put forth their feelers in an attitude of defence, and darted forth the poisonous fluid, with which we then discovered they were armed. This fluid was a strong acid; if it fell on the dress or gloves, the colour was instantly changed, or, if on the skin, it raised a blister. The work of extermination lasted nearly the whole summer. When the last day's slaughter was over, there were a few ants left. Whether they died in despair, or left the following morning, we did not discover. I was grieved for the cruel treatment they had received. Had they remained contented on the outside of our dwelling, they would not have been disturbed.- S. C. WHAT IS THE OBJECT?-"We not unfrequently hear the section of an Echinus spine pronounced 'very pretty, exactly like a crochet pattern,' the Echinus itself being an unknown thing. Spicales of Holotharia or Gregorica are brilliant little clubs or crosses, but what a Holotharia is they (many young persons who now purchase microscopes and collect objects) cannot imagine. The foot of a dytiscus, with its cluster of suckers, is like the eye of a peacock's feather; cells of spiral fibre nothing more than coils of variegated wire; and the head of Rhingia, with its wonderful eyes, is looked at as a beautiful piece of network . . . . To sit for an hour at the microscope, and pass slide after slide upon the stage with superficial attention, is not a worthy occupation for the great spirit within us."-S. S Clarke's "Objects for the Microscope." |