276 



NATURE 



\yan. 17, I < 



Ehrenberg's older nomenclature. Like Hertwig, I regard the 

 skeletonless Cystidium inerme, discovered by him (/.<-. pp. 87, 

 136, taf. vii. fig. i) as the ancestral form of the order. Cys- 

 tidium inerme is distinguished essentially from Actissa by the 

 restriction of the capsule pores to a single area, and the con- 

 sequent monaxonous fundamental form of the central capsule. 

 All other Nassellaria are derived from Cystidium by the 

 devel jpment of a characteristic siliceous skeleton. Hertwig 

 assumes that there are at least two or three entirely different 

 original forms for the Nassellaria skeleton, viz. a sirnple 

 siliceous ring (Lit/iocircus) fir the Cricoid skeleton of the 

 Acanthodesmida and Zygocystida, and a triradial siliceous 

 fr.imework consisting of three spicules united at one point 

 (/'■(»i,W(77«/'//a) for the Plagiacanthida and Cystida (I.e. p. 126, 

 &c.). I then endeavoured to refer these two fundamental forms 

 to a single form, as I made out the combination of the simple 

 siliceous ring and the triradial framework in many Cystida and 

 Spyroida (or Zygocystida). In my "Pridromus " (October, 1881, 

 /.(-. pp. 423-444) I divided the Nassellaria order into five 

 fanilie;, and placed the Pleclida (with triradial siliceous frame- 

 work) as the common ancestral group. From it I derived first 

 all the Cystida, from these again the Botiyoida and Spyrida 

 ( = Zygocystida), and from the latter the .Slephida (— Cr'i- 

 ciidea). At the same time, and quite independently of my re- 

 searches, Biitschli was busy with the same morphological 

 problem, and arrived at essentially the s.inie conclusion, except 

 that he reversed the phylogenetic series of the forms. In his 

 admirable treatise on the skeletons of the Cystida (also dated 

 October, 1881, published in the Zeit. f. ivissen. Zoohgie, 1882, 

 bi. 36, p. 485) he tries to prove the morphological connection 

 of all Na-sellaria (his Cricoidea), but regards the Slefhida 

 ( = .4 anthodesmida) as the primitive ancestral form, not as 

 the last degenerated scion, an opinion which I myself for- 

 merly shared (compare Hertwig, 1879, p. 126). Which of 

 these two opinions is correct cannot bedetermined at present. Im- 

 portant facts favour my present view, that the triradial siliceous 

 framework may be the common ancestral form of all Nassellaria 

 (Triflagia, Plagiacanthd). Again, other important facts favour 

 Biitschli's view that this ancestral form may be the simple 

 siliceous ring (Ltthocircus, Monostephus). Finally, there are 

 good grounds for supporting Hertvvig's opinion, that both these 

 ancestral forms (the triradial and the annular) may have ari en 

 independently from the skeletonless Cystidium. I shall discuss 

 this diflicult and intereUing question at length in my work on 

 the Challenger Radiolaria. 



IV. The Pha:odaria were only known up to 1876 by three 

 types described by me in 1862 (Auloeantha, Aulosplutra, Ca'lo- 

 dendrum). By the discovery of numerous forms in the Clial- 

 lenger collection this has since acquired an importance of which 

 we had no previous idea, as those Kadiolarians far surpass 

 all others both in size and singularity of form, as well as in 

 peculiar comliinations of structure. In my preliminary paper on 

 the Phreodaria, 1S79 (Jena. Naturwissen. .Silzungsb., December 

 12) I distinguished 10 families with 38 genera, a number which 

 has since been increased considerably by the continuous and 

 astonishing discovery of new forms. As in the majority of 

 these the skeleton is composed of hollow, siliceous tubes (differ- 

 ing therefore from tha* of all o'her Radiolarians), I termed the 

 while order Pansolenia, 1878 (" Protistenreich," p. 102). This 

 ninie, however, suits all members of the family as little as the 

 name Tripylea, proposed by Hertwig, 1879. On the other hand, 

 the present name Plueodaria indicates the common charac- 

 teristic of the whole order, the peculiar ph,rodium, a voluminou;, 

 dark body of pigment, lying excentrically outside the central 

 cap-ule. The latter is, moreover, universally distinguished by 

 its d luble membrane and by the pecul'ar opening furnished with 

 a radiated operculum, which lies at the pole of the axis, and may 

 therefore be termed the principal opening. In addition to it 

 there are usually (though by no means invariably) two small 

 accessory openings, lying one beside the other at the opposite 

 (aboral) pole. Sometimes there are more than two, whilst at 

 other limes they are entirely wanting. Despite the extraordinary 

 diversity of the peculiar, and often very complicated siliceous 

 skeleton, all Phccodaria may likewise be derived from a common 

 ancestral form — the skeletonless Pluvodina. 



The further phylogenetic question, whether all the hypothetic 

 primitive forms already mentioned of the four Radiolarian 

 orders can be refeixed to a single common primitive form, may 

 now in all probability be decided in the affirmative. From 

 Aetissa the parent form of the SpnmcUaria, the ancestral form of 



the three other orders may be derived without difficulty. Aeti- 

 niliu!, the ances'ral form of the Acantharia, may have arisen 

 from Actissa by the thickening of part of the radial pseudopodia 

 into acanthine spicules. Cystidium, the probable ancestral furm 

 of the Nassellaria, may be derived from Aetissa by the pores of the 

 capsule membrane, originally developed equ.illy and on all sides, 

 becoming restricted to a single distinct porous area. Phieodina, 

 the ancestral form of the Ph;Eod.aria may have arisen in a similar 

 way from Actissa by the porous area becoming replaced by a 

 single, simple opening, or small, additional, accessory openings, 

 still being left, whilst at the same time the capsule membrane 

 became double, and the pigment mass of the phaiodium de- 

 posited excentrically round it. Whilst, on the one hand, the 

 simplest Spumellaria form, Actissa, maybe easily accepted as the 

 ancestral form of all Radiolaria, AetinospJuehum and Actino- 

 phrys .show, on the other hand, how it may be derived fro'n 

 the simplest Rhizopoda. 



( To be continued. ) 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE 



Thf. Technical Schools in connection with the University 

 College, Nottingham, will be formally opened by Sir Frederick 

 Bramwell on the 24th inst. 



Mr. J. T. Dunn, M.Sc, Demonstrator in Chemistry at the 

 College of Science, Newcastle, and formerly Demonstrator in 

 Physics, has been appointed Science Master and Director of the 

 Chemical Laboratory in the High School for Boys, Gateshead. 

 In the Gateshead High School, which opened in May 1883, 

 there are already about 175 boys, and it is intended that all the 

 boys shall learn Physics and Chemistry at some period of their 

 school course. 



SCIENTIFIC SERIALS 



y ournal of Franklin Institute, vol. cxvi. No. 696, December, 

 18S3. — The cheapest point of cut off, by W. D. Marks. Par- 

 tially based on, and in criticism of, a previous paper by Mr. 

 Hill, — Experiments upon non conducting coverings for steam 

 pipes, by Prof. J. M. Ordway. In this research calorimeters 

 are used, consisting of sheet-brass vessels so shaped that they can 

 be clamped together outside the steam pipe, inclosing a known 

 length of it and of its covering. Of more than fifty substances 

 tried, simple hair-felt with a cheap cover of burlap proved best ; 

 seventeen other compositions owed their efficiency to hair. 

 Asbestoi hard pressed was a very bad material ; it was non-con- 

 ductive only in the downy state when full of air. — Pressure attain- 

 able by the use of the " Drop Press," by Prof. R. H. Thurston. 

 These presses appear to be very efficient for forging hot iron.- — 

 The theory of turbines, by Prof. R. H. Thurston. This is the 

 first part of an abstract of a most valuable mathematical discus- 

 sion of the subject. — A new valve-motion, by Carl Angstrom. 

 This is a so-called "radial" valve-motion, resembling those of 

 Brown, Marshall, and Joy. — A simple and sensitive thermostat, 

 by Dr. N. A. Randolph, designed for incubation and other 

 experiments in the physiological laboratory. The adjustment is 

 obtained by the more or less closing of the orifice for the gas by 

 the expansion of alcohol causing mercury to rise toward the 

 orifice. 



Annalen der Pliysik und Chemie, xx. No. 12 (a), December, 

 1S83. — On the condensation of carbonic acid on smooth surfaces 

 of glass, by Prof. R. Bunsen. The condensation of the gas 

 goes on for years, in spite of continual changes of density and 

 pressure. In three years each square centimetre absorbs, at 

 standard pressure and temperature, 5'I35 cubic centimetres of 

 the g.rs, about two-thirds of this amount being absorbed during 

 the tir.,t year. — Density proportions of normal salt solutions, by 

 C. Bender.— The law of rotational dispersion, by E. Lommel.— 

 A simple method of investigating the thermo-, actino-, and piezo- 

 electricity of crystals, by Prof. A. Kundt : consists in applying 

 Lichtenberg's powder. — On the measurement of electric forces 

 by means of the electric mill, by D. Kaempfer.— On the ques- 

 tion whether the condensation of steam produces electrification, 

 by S. Kalischer. — On the influence of the hardness of steel on 

 its magnetisability, by V. Strouhal and C. Barus : also, on the 

 influence of annealing on the retentivity of the magnet, by the 

 same authors. These are two very elaborate and important 



