March 30, 1893] 



NATURE 



525 



without differentiation of organs, grows out into several finger- 

 shaped processes, which are generally directed towards the 

 distal end of the ovicell" . . . "the^e finger-shaped processes 

 are divided up by a series of transverse c )n-itrictions into rounded 

 masses of cells, each of which becomes a complete larva ; " the 

 few rare ca-ses in the Tunicates and Coelenterata, where the 

 asexual reproduction of buds takes place from very feebly de- 

 veloped embryo forms are cited. — On two new genera and some 

 new species of earthworms, by Frank E. Biddard, F. R.S. 

 (plates XXV. and xxvi.). Describes Trichochceta hesperidum, 

 nov. gen. et spec, from Jamaica ; Alvatiia millsoni, nov. gen. 

 et spec, from Lagos ; Polytoreuttis magilensis, n. sp. from 

 Magila, East Central Africa; and Py^/naocirilui lacuum, n. sp. 

 from Lagos. There are also notes on Siphonogaster millsoni, 

 F. E. B. — Observations on thegregarinesof Hjlothurians, by E. 

 A. Minchin, B. A. (plates xxvii. and xxviii. ). These gregarines 

 apparently first indicated by Kolliker, and identified by 

 Schneider (1858), have since been studied by Cuenot, Min- 

 gazzini, Ludwig and Leger, and have now been closely in- 

 vestigated from fresh material found at Naples and Plymouth, 

 by the author. Gregarina irregularis, n. sp. found on the 

 blood vessels of Holothuria, at Plymouth, is described ; nume- 

 rous details about the spores and sporozoites are given, and the 

 difficult question of the affinities of these forms is discussed. — 

 A new Sporozoon in Amphioxus, by E C. Pollard (plate 

 xxix.). These minute parasites were discovered in the epithe- 

 lium of the intestine. Miss Pollard also figures a ciliate Proto- 

 zoan found in the atrium of Amphioxus, which had been found 

 some time back by Prof. Ray Lankester, he suggests that 

 possibly the Sporozoon may be a stage in the life history of the 

 ciliate form. — Studies on the Protochordata, by Arthur Willey. 

 I. On the origin of the branchial stigmata, praeoral 

 lobe, endostyle, atrial cavities, &c., in Ciona intestinalis, Linn., 

 with remarks on Clavelina lepadiformis (plates xxx. and xxxi.). 

 As the result of prolonged and very complete investigations, 

 the author finds himself compelled to completely alter his pre- 

 viously published views as to the homologies existing between 

 the various organs of the Ascidians and Amphioxus. 



Wiedemann' s Annalen der Physik und Chemie, No. 3, 1893. 

 —Electromagnetic theory of colour dispersion, by H. von 

 Helmholtz. A mathematical deduction of Fresnel's and 

 Cauchy's formulae from the electromagnetic theory of light by 

 means of an application of the principle of least action to 

 electrodynamics. — Magnetisation of a radially slit iron ring, by 

 Heinrich Lehmann. The method employed was practically 

 that of Ewing, with ballistic measurement. The normal curve 

 for the closed ring was first determined. The ring was then slit 

 radially, and the width of the slit regulated by plane parallel 

 discs of brass introduced between the faces, the ring being 

 tightened by a brass collar whenever necessary. To measure 

 the flow of induction through the slit, the bras^ disc was wound 

 with a number of turns of very fine copper wire. The width 

 of the slit was varied from 0*4 mm. to 357 mm., and the 

 strength of the magnetic field from i to about 300. It was 

 found that the coefficient of dispersion, i.e. the ratio of the 

 mean induction to that at the slit, increased with the. width of 

 the slit and finally decreased with increasing field intensity. 

 The divergence of lines of force was practically limited to the 

 neighbourhood of the slit. For each width of slit the coeffi- 

 cient of demagnetisation was c mstant up to about half saturation 

 point. A formula is given for calculating this coefficient from 

 the geometrical dimensions of the system. — On the influence of 

 temperature upon circular ferromagnetic polarisation, by Emil 

 Hirsch. Transparent plates of iron, nickel and cobalt were 

 prepared by electro deposition upon a transparent film of 

 platinum burnt into a gla=is plate 2 mm. thick and free from 

 double refraction. Lippich's half-shadow polarimeter was used 

 for measuring the circular polarisation. The light was furnished 

 by a zirkonium burner, and the magnetic field by a large 

 electromagnet fed with a current of 33 amperes giving a field 

 of 9000 CO. S. units. The metallic film? were enclosed in a 

 brass box heated by two Bunsens, the temperatures being 

 measured by thermometers and an irongermansilver-thermo- 

 pile. As a result, Kundt's constant, or the ratio of the rotation 

 of the plane of polarisation to the increase of *' magnetisation 

 potential " from one side of the film to the other, was found 

 to be independent of the temperature within the limits 

 of observational error. — Also papers by E. Lommel, F. 



NO. 1222, VOL. 47] 



Richarz, K. Angstrom, H. Ruoss, P. Druie, and H. E. J. G. 

 du Bois. 



Bulletin de I'Aca leinic Royale de Belgique, No. 2, 1893. — We 

 notice the following pipers: — On a new form of blende, by G. 

 Cesaro. Thespecimen occurred inthegranulardolomiteof Binnen, 

 in the form of a light yellow translucent crystal 3 mm. in dia- 

 meter. Its crystalline form is that of the tetrahexahedron, the 

 trihedral angles being truncated by striated scalene triangles. — 

 A new electrical pro:ess permitting the production of tem- 

 peratures superior to those actually realisable, by Eug. Lagrange 

 and P. Hoho. The new method consists in the passage of a 

 current through a conducting liquid by means of electrodes, one 

 of which is made of the substance to be raised by a high tem- 

 perature. M. VioUe has recently estimated the temperature of 

 the electric arc at 3500° C. and found that it is constant, so 

 that it represents the highest temperature attainable by that 

 method. In the new method the heat is developed at the sur- 

 face of the electrode. During the passage of a current of, say, 

 2000 volts and 150 amperes through a 10 per cent, solution of 

 sulphuric acid, a layer of gas is formed round an electrode con- 

 sisting of a plate of graphite, and since the resistance of the 

 circuit is concentrated in this layer of gas, practically the whole 

 energy of the current is transformed into heat in the immediate 

 vicinity of the substance to be operated upon. The temperature 

 rises until the amount of heat, dissipated by conduction and 

 radiation, is equal to that produced. If the production of heat 

 is very rapid, this limit will be very high, and the temperature 

 obtainable depends simply upon the strength of the available 

 current. 



Annalen des K. K. Naturhistorischen Hof museum;. Bd. vii. 

 (Wien, 1892).— The last two parts (Nos. 3 and 4) of the seventh 

 volume of the Annals of the Royal Natural History Museum of 

 Vienna fully maintain the credit of this publication. — In his 

 Contributions to the knowledge of the Crustacea of the Canary 

 Islands, K. Koelbel describes and figures Livoneca sulcata, 

 n.sp. and Munidopsis polymorpha, n.sp. — The species of 

 Alectoria and their geographical distribution, by Dr. E. 

 Stizenberger. — A contribution to the morphology of Corundum, 

 by Dr. H. Barvir. Two twin sapphires are described and 

 figured. — In Part II. of his " Meteoric Siudies " E. Cohen gives 

 analyses of twelve American meteorites. — Two plates illustrate 

 F. Siebenrock's paper on the skulls of the Scincoidse, Anguidae, 

 and Gerrhosauridae, twenty-six species of the first and three each 

 of the second and last are referred to. — New forms of Hymenop- 

 tera, by F. F. Kohl (three plates), thirty-eight new species are 

 described and one new genus Hdiocausus. — On the typical 

 specimens of Lacerta mosorensis, Kolomb. (1886) (= Lacerta 

 koritana, Tom. 1889) by Dr. F. Steindachner (pi. xvi.). — Con- 

 tributions to the Microlepidopteran fauna of the Canary 

 Archipelago, by Dr. H. Rebel (pi. xvii.). Ten. new species 

 and two varieties are described and figured, and one new genus, 

 Hypotomorpha. The paper concludes with a valuable index and 

 table of the geographical distribution of sixty three Microlepi- 

 doptera ; the distribution includes west and east Canary Islands, 

 Azore; and Madeira, N.W. Africa, Mediterranean region, 

 and other regions. — Part IV. contains the following papers : — 

 Remarks upon the species of the genus Potamogeton in the 

 Herbarium of the Royal Natural History Museum, by A. 

 Bennett; three new species are described. — Compositae Hil- 

 debrandtianae et HumSlotianae in Madagascaria et insulas 

 Comoras collectae, by Dr. F. W. Klatt (six new species). — 

 Lichenes exotici Herbarii Vindobonensis, by Dr. J. MitUer. — 

 The birds of Austro-Hungary and of the land of occupation in 

 the Royal Natural History Museum of Vienna, by Dr. L. R. 

 L. V. Liburnau. — On vertebral assimilation among the Lizards, 

 by F. Siebenrock. Normally but two sacral vertebrae support 

 the pelvis in lizard.s, but in 1864 Hyrtl described under the term 

 " Wirbelassimilation " deviations from this rule. In this paper 

 several examples are given in which the last lumbar or the first 

 caudal vertebra is connected with the pelvis ; a figure is given 

 of the latter arrangement in a specimen of Uromastix spinipes, 

 and of the former in a specimen oi Lacerta Simonyi. The last 

 paper — Old Mexican relics from the Castle Ambras in the 

 Tyrol, by F. Heger — is of ethnological interest. Four photo- 

 graphic plates, and one in colours, illustrate this paper, and, 

 like the majority of the illustrations of this journal, are of the 

 highest excellence. 



