1857/01/01 by Louis Agassiz · 4 citations
Agricultural and Biological Sciences · Social Sciences · #Archaeology #Archaeology and Natural History #Biology #Botany, Ecology, and Taxonomy Studies #Ecology #Economic history #Environmental ethics #Genealogy #Geography #History #History of the United States #Natural (archaeology) #Natural history #Philosophy #Plant and animal studies #Political science
paper · doi:10.5962/bhl.title.12644
openalex publication_date 1857/01/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
acquaintance with the labors of their predecessors.The study of the Acalephs, under which name naturalists now include the so-called jelly-fishes or sea-blubbers or sun-fishes, and the animals allied to them, affords a striking example of this correspondence between the gradual progress every one must make who attempts to understand their nature, and the successive stages of the science relating to these animals as recorded in the works of the authors of past ages.When we first observe a jelly-fish, it appears like a moving fleshy mass, seemingly destitute of organization ; next, we may observe its motions, contracting and expanding, it floats near the surface of the water.Upon touching it, we may feel the burning while sensation it produces upon the naked hand, and perhaps perceive also that it has a central opening, a sort of mouth, through which it introduces its food into the interior.Again, we cannot but be struck with their slight consistency, and the rapidity with which they melt away when taken out of the water.But it is not until our methods of investigation are improved; and when, after repeated failures, we have learned how to handle and treat them, that we begin to perceive how remarkable and complicated their internal structure is ;-it is not until we have become acquainted with a large number of their different kinds, that we perceive how greatly diversified they are;-it is not until we have had an opportunity of tracing their development, that we perceive how wide the range of their class really is ;-it 1s not until we have extended our comparisons to almost every type of the animal kingdom, that we can be prepared to determine their general affinity, the natural limits of the type to which they belong, the distinctive characteristics of their class, the gradation of their orders, and the peculiarities that may distinguish their families, their genera, and their species.We cannot, therefore, expect to find, in the older writers upon Zovlogy, any thing like a natural classification of these animals.Even Aristotle, whose keen mind has thrown so much light at such an early period upon Cuap.I. HISTORY OF THE ACALEPHS.5 ACALEPHS IN GENERAL.Part I.all that is said about Acalephe and Knide, it would seem as if the name of Knidx applied more particularly to Medusx, as these are the only ones of which he seems to have known that they possessed burning properties, the nature of which could not have been very clearly understood by him, for he says, when speaking of the Sea Scolopendra (probably some Nereis), that it does not bite with the mouth, but produces with the whole body a painful sensation like that caused by the Knide.The description he gives of the Acalephx applies particularly well to the Actiniaw, and but for the statement that they free themselves could not be applied to any Medusa.Of the Pneumon, he only states, that they are formed out of themselves.Neither Pliny? nor Aelian nor Oppian nor Galenus, nor the writers of the middle all; and, suffering from the heat, they retire furtherIn Book VIII.Chap.I. Sec. 5, when, speaking of the among the rocks."intensity of life and_ its gradations, he considers the marine shells and the Ascidians as intermediate between the higher animals and plants."The transition from them to the animals is uninterrupted, as has been said before ;as to some of those in the sea, one might doubt whether they are animals or plants, for they are attached, and many of them, when separated, are destroyed.In some, the nature of the body is fleshy, as in the so-called Tethya (our Ascidians)and the genus of the Acalephe.The sponge, however," he adds, "is entirely like the plants"; and in Chap.III.Sec. 3, he says that "the Acalephw live upon whatever small fishes fall in their way, and that they have the mouth in the middle, which is most evident in the largest ones.They have also, like the oyster, an opening where the food passes out, and this is upward.In a general way the Acalephw resemble the internal fleshy part of the oyster, and it uses the rock as a shell."First, in Book V. Chap.XIV.Sec. 1, where it says that "the Knide and the Sponges, which are found in the The name IKnide occurs twice.clefts of the rocks, though without a shell, multiply There are, however, two genera of Knidwe: one in the hollows, in the same way as the shell fishes.which never frees itself from the rocks; and another, living upon flat, smooth bottom, which detaches itself And in Book IX.Chap.XXV.See. 4, when speaking of the seasnakes, he says of the Sea Scolopendra (our Nereis), and moyes from place to place."that "when it has swallowed the hook, it turns itself inside out until it expels the hook, and then turns itself back again; it does not bite with the mouth, but its whole body produces a painful sensation, like that of the Knide."The name Pneumon occurs but onee (Book V.Chap.XHI.See.10), when, speaking of the reproduction and growth of animals, he only says that the so-called Pneumon "is formed from itself," meaning that it is spontaneously generated.From this passage it could hardly be inferred that Aristotle designated an Acalephe under the name of Pneumon.But when we consider how the Grecian colonies were scattered along the shores of the Mediterranean, and that the name Pulmo Marinus was early applied to the large Rhizostoma of the Mediterranean, and even figured under that name by Mathioli; that the Rhizostoma may aptly be compared to a floating lung; and further, that this largest Medusa of the Mediterranean is commonly called Poumon de Mer by the French fishermen, -the conclusion is irresistible, that, if thes Latin and French names are not a translation of the Greek "Pneumon," this name is likely to have been given to that large Medusa for the same reason for which the French call it sea-ling.It is singular, however, that Rondelet, who first represented the Rhizostoma, should have failed to recognize it as the Pneumon of the Greeks, and applied the name to a compound Ascidian.1 The best edition of the Natural History of Pliny is that published in Paris in 1828 by Lemaire, under the supervision of Ajasson de Grandsagne : CuAr.I. HLSTORY "OF THE ACATE PHS. 9that neither Polyps nor Acalephs nor Mollusks will exhibit their natural appearance when taken out of the element in which they live, it is still to be lamented that both the star-fishes and sea-urchins are everywhere represented as they appear when taken out of the water, and all their soft appendages, so numerous and diversified, are drawn in or so contracted and collapsed as no longer to give the slightest idea of their natural beauty.Like Aristotle, Rondelet still unites the Actinia and Acalephe under the name of sea-nettles (Urtica marine), distinguishing the former as the fixed sea-nettles and the latter as the free sea-nettles.Even Cuvier, in his earlier works, allows these animals to remain together, though it was he himself who.sepa-Rude as are the illustrations published by Rondelet, it is hardly possible to mistake in his rated them afterwards, for the first time, as members of two distinct classes.fifth species the Rhizostoma of Cuvier, although the disk is too small and the arms too straight, and in the sixth the Chrysaora of Péron, although Linnzus refers that figure to the Aurelia aurita.In the writings of Aristotle a single part of the Acalephe is distinguished by name, -the mouth, which occupies the centre of the body, of which nothing is stated except that it is fleshy.The passage already quoted from Pliny (Lib.EX. ch.45) speaks of leaves ("ac praenatante pisciculo frondem suam spargit"), no doubt meaning by frons the thin, expanded margin of the disk, and the appendages about the mouth, which he considers as a root ("ora ei in radice esse traduntur"), thus carrying out a comparison of these beings with plants.Rondelet, on the contrary, vindicates especially their animal nature when he says, that since they alternately expand and contract their blade, which serves as feet, and since they absorb food through the mouth and thus show themselves provided with the senses of touch and taste, which are essential to the animal life, he considers them as imperfect animals, and not as Zobphytes, as Pliny does.Speaking of the small sea-nettle, which is his first species, he mentions its short tentacles, and its resemblance to the large intestine, thus distinctly pointing to the genus Actinia, of which, he says, there are several varieties, some green, some blue, some blackish, with blue, yellow, or red spots.His second species seems to be a Tubulibranchiate Annelid, for he says it bites.His third species is another Actinia, with which he confounds the ASquorea of the Mediterranean.' * Tn my next Monograph I shall have an opportunity of representing the North American Echinoderms as they appear in life.* Cum igitur Urtice frondem suam, que pedum vice est, modo dilatent modo contrahant, cum ore cibum accipiant, id est, cum tactu gustuque, qui duo sensus ad yitam animalium sunt necessarii, pradite sint, non inter Zoophyta, ut Pliuius, sed inter animalia VOL.Il. 2 non omnino perfecta, eas numerabimus.Rondeletius, Lib.XVII.p. 527.® Tt can hardly excite surprise to find, that, with as little knowledge as Rondelet possessed upon the subject of Acalephs in general, he should have confounded a Medusa and an Actinia, especially when it is remembered that the numerous radiating tubes of the /Equorea give it a greater resemblance to an ACALEPHS IN GENERAL.Pang I.The fourth species is unmistakably the Actinia senilis.Speaking of the fifth species, which is the Rhizostoma, he compares the disk to a hat, and the eight pendant appendages to the feet of the Octopus.Of the sixth species, he says that the four feet may be compared to Acanthus leaves.'Gessner, in his great Natural History of the Animals, has followed Rondelet for the Acalephe, as he did for most of the other productions of the Mediterranean; and also copied his figures and those of Bélon, adding only such remarks as exhibit his vast erudition, but in no way a better acquaintance with the animals themselves?It has been a source of constant delight for me, while perusing the works of the earlier naturalists, to sympathize with the genial spirit and the earnestness that pervade their writings, so free from egotism, and animosity against their fellow-students.Their devotion to their studies is equal to the spirit of reverence with which they look upon nature; and it is disgraceful to our age, that we must contrast with such dispositions the ill-will, the jealousies, the quarrels for priority, and the profanation, which pervade the discussions of certain modern authors.Moreover, in a systematic point of view, the great naturalists of the sixteenth century deserve to be studied more fully than they have been thus far.It is astonishing, for instance, to see how near Rondelet, in discussing the views of Aristotle upon the affinities of animals, came to perceiving their true affinities, and their natural classification under four great types.In the Ist Chapter of the 17th Book of his great work, " De Piscibus Marinis," after describing the fishes of the Mediterranean, he says, that having thus deseribed the Enwina,-that is, the animals provided with blood,-he now proceeds to describe the Anaima, among which he distinguishes the Malakia in contradistinction to the S#leoderma.These Malakia are the Cephalopoda, to which unfortunately the Medusx are added on account of the appendages around the mouth, which were compared by him to the feelers of the cuttle-fish.In Book 18th he treats of the Crustacea under the name of Malakostraca, and distinguishes from them the Ostrakoderma, or shell fishes, Actinia than any other Medusa has; but that he did 2 An interesting notice of the life and writings confound the two is plain from the following words :"Saxis aliquando hewret, aliquando soluta vagatur."The purple color of the AEquorea may also have contributed to mislead him.1 Tlere, then, we have for the first time the word pileus (hat) introduced to designate the disk of the Medusex, an expression that has been retained by most later writers, while some zodlogists have substituted for it the name of wnbrella, or disk; while the word feet stands for the appendages around the mouth, to which the name arms was afterwards more generally applied.of Gessner, by Cuvier, may be found in the Biographie universelle, vol.17, and in the Histoire des sciences naturelles, vol.2, p. 835.I would gladly also refer to the notice by Blainyille in his Histoire des sciences de lorganisation; but that chapter is so interwoven with jesuitical insinuations as to be utterly unpalatable to a sober thinker.