2 74 



NA TURE 



[jfan. 17, 1884 



to a great numlier of flowers, and has come to the conclusion 

 that, however yreat the analogy between the petals and the 

 leaves, still the former have a series of well-established anatomi- 

 cal features which enable us to characteri'^e them as well as any 

 i>ther part of the plant. Some of their anatomical features can 

 be explained by the physiological function of the organ, whilst 

 the others have no connection with them, and the explanation 

 of these peculiarities must be sought for elsewhere — says the 

 author — in the yet unknown internal structural form of the plant 

 as also, perhaps, in the position occupied by the flower in the 

 whole of its organic life. 



In chemistry and physics we notice two papers, by M. Tana- 

 tar, on the fumaric and maleinic acids (vol. vi.), and on their 

 compounds with chlorite (vol. viii.) ; by M. Klimenko, on the 

 lactic and propionic acids (vol. vi.) ; by M. Melikov, on the 

 compounds of acrilic acid; and by M. Geritch, on electrical 

 phenomena observed during the diffusion of several liquids. 



A paper of general interest, intended to show some relaiions 

 between animals and plants at their lowest degrees of develop- 

 ment, is contributed by M. .Shmankevitch (vol. vii.). When 

 the Flagellate, Anisonema acinus^ Bliitochli — having a relatively 

 high organisation — is cultivated for many generations in a 

 medium which is slowly modified, for instance, in sweet water 

 to which a certain amount of lake salt is added, its structure is 

 modified, in proportion as the concentration of the solution of 

 salt is increased. The individuals become less developed, their 

 size diminishes, and the feeding-canal loses its former develop- 

 ment. Numberless intermediate forms betvi'een the Anisonema 

 acinus and its new, less developed representatives, make their 

 appearance, as well as between these and the still lower Aniso- 

 nema sulcatum, which would be thus but a lower organised 

 variety of the former. When the concentration of the medium 

 in which the Anisonema lives is carried on side by side with a 

 change of temperature of the medium, the transformation goes 

 further on, and the lowest Anisoneniu are transformed on the 

 one side into algje-like organisms, and in another direction into 

 organisms which seem to belong to the category of fungi. The 

 individuals not only become smaller, but they give rise also to a 

 progeny long before reaching their full size. Under the influence 

 of the sun's rays the uncoloured Flagellatse acquire a new physio- 

 logical function, and develop chlorophyll. " We see thus," the 

 author says, "the beginnings of two kingdoms, animal and vege- 

 table, radiating from one common stem. We see the transforma- 

 tion of one of them into the other, not only in its morphological 

 features, but also in its physiological functions, under the direct 

 influence of physical and chemical agencies. The saline solutions, 

 as compared with sweet water, diminish the size of the lower 

 organisms, and at the same time they contribute towards the 

 development of chlorophyll in the sweet-water algje, thus giving 

 them, so to say, a more vegetable character, together with an in- 

 creased productivenes." And further : "While descending from 

 the Anisonema sulcatum to a unicellular alga, we see the regres- 

 sive development, a simplification of organisation; ^\e descend 

 towards the plants containing chlorophyll. . . . While descend- 

 ing from the same Anisonema on another branch, we enter 

 into the region of such lower organisms which, under the 

 influence of another medium, do not develop chlorophyll, and 

 having no nutrition from the air, find their food from the sub- 

 stratum ; they could be described as parasitic Rhizopodre, and 

 ♦his the more as from the fungoid form we can ascend, under some 

 circumstances, not only towards the Amceba-Iike uncoloured 

 Flagellata, but also towards the moving Monad. On the 

 contrary, by reversing the physical agencies, we can arrive, from 

 the unicellular alga, as well as from the fungoid form, to 

 an uncoloured form having the structure of the Anisonema^ 

 The researches of A. Giard, Cienkowsky, and Famintzyn, 

 and some observations by Ray Lankester, seem to be, in the 

 author's opinion, in accordance with the above. 



PROFESSOR HAECKEL ON THE ORDERS OF 

 THE RADIOLARIA ' 



[The following translation of a recent paper of mine, by 

 Miss Nellie Maclagan, has been revised by myself. — Ernst 

 Haeckel.] 



"T^HE "Outline of a Radiolarian System founded on Studies 



of the Challenger Radiolaria," published by me in the 



jfenaische Zeitschriftjiii- A'atu>~wissenscha/i(m. xv. pp. 418-472), 



* " Separat-Abdriick aus den Sitzungsberichten der Jenaischen Gesellschaft 

 fiir Medicin. und Wissenschaft." Jahrg. 1883. Sitzung. von 16 Februar. 



shortly before starting for Ceylon in October, 1881, gave a very 

 short survey of the systemalii. results of the researches which I had 

 been carrying on since 1876 among the inconceivably rich 

 Radiolarian material of the C/iallenger collection. At that time 

 I distinguished in tliis Rhizopod class seven different orders (p. 

 421) and 24 families, containing in all 630 genera (" Prodromus 

 Systematis Radiolarium," I.e., pp. 423-472). I was able even 

 then to distinguish no less than 2000 new species, and this goodly 

 number has since been considerably increased. Further investi- 

 gations corroborated all the principal essential points of the 

 views then briefly given as to the morphologico-phylogenetic 

 conditions of relation among this Protista class, liut I gradu- 

 ally came to simplify my views as to the relation of the 

 principal groups, and have now reduced the seven orders 

 to four, which makes the complicated system much more com- 

 prehensible. 



The systematic arrangement of the 15 families, given in my 

 " Monographic der Kadiolarien," 1862 (following Johann Midler, 

 who first broke ground in his treatise, 1858) was essentially 

 improved by Richard Hertwig, whose admirable work on the 

 " Organismus der Radiolarien," 1S79, thoroughly explained for 

 the first time the difficult histology of these Protista, and definitely 

 determined their unicellular nature, despite all peculiar modifi- 

 cations of the cell structure. On the ground of important differ- 

 ences discovered by him in the structure of the membrane oi the 

 central capsule, and the consequent varying comportment of the 

 passage of pseudopodia, Hertwig distinguished the following 

 six orders {I.e. \i. 133) : — I. T/ialassicolleir, monozoic uninuclear 

 Radiolarians, having the capsule membrane pierced on all sides : 

 skeleton siliceous, irregular, or wanting. 2 Sphttrozoea, polyzoic 

 multinuclear Radiolarians, having the capsule membrane pierced 

 on all sides : skeleton siliceous, irregular, or wanting. 3. 

 Peripylea, monozoic uninuclear Radiolarians, having the capsule 

 membrane pierced on all sides : skeleton siliceous, consisting of 

 fenestrated spheres or modified fenestrated spheres or disks. 4. 

 AeantJiometrea, monozoic uninuclear Radiolarians, having the 

 capsule membrane pierced on all sides : skeleton non-siliceous, 

 consisting of twenty spicules arranged according to J. Miiller's 

 law. 5. Monopylea, monozoic uninuclear Radiolarians, the 

 capsule open on one side, and with a peculiar porous area : 

 skeleton siliceous. 6. Tritylea, monozoic uninuclear Radio- 

 larians ; capsule membrane double, with one principal and two 

 accessory openings; skeleton siliceous, formed of tubes. 



As I found that the imporlant differences in the structure of 

 the membrane of the central capsule and the con.'^equent passage 

 of the pseudopodia, discovered by Hertwig in the comparatively 

 limited material at his disposal, were corroborated in their mot 

 essential points by my researches among the wider world of the 

 Challenger Radiolaria, I adopted his sclieme in my " Con- 

 spectus Ordinnm Radiolarinm Classis," iSSr {I.e. p. 421), but 

 with this difference, that I divided Hertwig's Splurrozoea into 

 tHO orders — Sy>nbelaria and Syncollaria. The latter, Syneol- 

 laria, includes the families of the Sphitroizoida in the wider 

 sense, and, from the absence or incompleteness of the skeleton, 

 corresponds as a polyzoic group to the monozoic Thalassieollea, 

 whilst the former, Symbelaria, includes the family of the Col- 

 lospharida in the wider sense, and by its spherical, reticulate, 

 siliceous skeleton corresponds as a polyzoic group to the mono- 

 zoic Peripylea. 



Recent researches, which have brought to light an immense 

 number of new, hitherto unknown Radiolarians belonging to 

 the last-mentioned groups, have, however, convinced me that the 

 distinction between the monozoic (solitary) and the polyzoic 

 (social) Radiolarians is of much less importance than v as for- 

 merly supposed. They are as insignificant and of as little value 

 in forming a system as the differences between monozoic Hy- 

 dropolyps (e.g. Hydra, Myriothela) and polyzoic Hydropolyi^s 

 {Tnbularia, Coryne), or as the difltrences between solitary In- 

 fusoria {Vorlicella, Prichodina) and social Infusoria (Ca«/;«;««;, 

 Epistylis). According to Hertwig, the essential difference 

 between the two groups is that the solitary Thalassieollea are 

 uninuclear, the .social Sph.erozoea {= SyniMaria) multinucUar. 

 Nevertheless, the central captule in all Radiolaria (without ex- 

 ception) is uninuclear at an early stage and multinuclear later 

 on. We would require to be more exact about this distinction, 

 inasmuch as in the Sphierozoea ( = as in the Acanthometrea) the 

 division of the simple nucleus into a number of nuclei 'sjiore 

 nuclei) takes place at a very early period, whilst in the Thalas- 

 sieollea (as in the other Radiolaria) it only takes place later on. 

 This relative modification i'^, however, of no standard value 



