Aug. 31, 1876] 



NATURE 



383 



layers in Mollusca. He especially calls in question the obser- 

 vations of Ray Lankester, Haeckel, and Ganin, and approves 

 the modified form of the Gastrjea theory no more than the 

 original — F. E. Helm describes in detail the silk-glands of 

 Lepidoptera, and their retrogressive changes after full function. 

 — Herbert Ludwig, giving an account of the formation of the 

 blastoderm of spiders, states that his observations are in entire 

 accordance with Haeckel's views. 



Gegenbaur's Morphologisches Jahrbuch. — Part 3 opens with 

 a long and important communication by Oscar Hertwig on the 

 formation, fecundation, and division of the ovum in the Echinid 

 Toxopneustes lividus. He considers chiefly the fate of the germinal 

 vesicle and the connection between it and the subsequent deve- 

 lopment of the ovum. From his observations he supposes that 

 when the germinal vesicle is resolved the germinal spot is saved 

 and gets to the centre of the ovum ; he finds that a nuclear body 

 which may be the head of the spermatozoon approaches this and 

 coalesces with it, and that the resulting body assumes an hour- 

 glass shape and finally divides into two, and really originates 

 the cleavage of the ovum. Unfortunately the author has to make 

 assumptions at the most critical pouits, and consequently his 

 views cannot be accepted without confirmation. — Dr. G. Born 

 has a contribution on the sixth toe of Anura, referring to the 

 cartilages considered by Cuvier and Meckel as a rudiment of a 

 sixth member of the hind limb. Another lengthy memoir in 

 this part is by R. Wiedersheim on the anatomy of Phyllodactylus 

 eurtpceus, a member of the group of lizards of which the gecko 

 is the type, found in the Island of Sardinia, as well as in the 

 islet Tinetto, on the western horn of the Gulf of Spezia. He 

 considers very fully the relation of the aqueductus vestibuli to the 

 sacculus endolymphaticus in the Ascalabota generally. 



In Part 4 Ur. B. Gabriel describes a new genus and species 

 of Rhizopod living in moist earth about the roots of mosses. 

 This form, which he names Troglodytes zoster, has a shell-like 

 investment and emits pseudopodia at one pole only. The life- 

 history of this form has been traced, and it is of great interest. 

 Two adult specimens conjugate by their pseudopodia and after- 

 wards separate ; this is followed by an encysted stage, during 

 which a large number of minute granules grow up into germs 

 which are liberated from the investment, and grow up into a 

 minute monostigma form. These germs subsequently conjugate 

 in pairs constituting a diplostigma, and ultimately they slowly 

 coalesce, and then assume the parent form. — T. W. Engel- 

 mann has an elaborate article on development and reproduction 

 in Infusoria, in which he gives an account of the stages of 

 Opalina ranarujn and of budding and conjugation in Vorticella 

 and Epistylis. He further examines and criticises many observa- 

 tions of other authors, and some of his principal conclusions are 

 as follows : — That the conjugation of Infusoria does not lead to 

 reproduction by means of ova, but to a peculiar development of 

 the conjugated individuals, .which he terms reorganisation ; that 

 the nucleus, neither in conjugation nor in any other circumstance, 

 plays the part of a germ-producing organ ; that its significance 

 is merely that of an ordinary cell-nucleus. — Max FUrbringer con- 

 tinues his monograph on the comparative anatomy of the 

 shoulder- muscles, by a chapter of 180 pages, on the bony 

 shoulder-girdle and sternum, the brachial plexus, and the muscles 

 related to the shoulder in Lacertilia and Crocodilia. 



SOCIETIES AND ACADEMIES 



Philadelphia 

 Academy of Natural Sciences. — Session 1875-6. — Prof. 

 Cope's contributions to palaeontology and philosophic biology 

 have been numerous and important. In successive communica- 

 tions he has given accounts of the Eocene mammals of the Rocky 

 Mountains, possessing characters which at first led to their being 

 assigned to the Carnivora. Prof. Cope has demonstrated their 

 insectivorous affinities, but finds that the definition of existing 

 insectivora is insufficient to include them. Other forms supposed 

 at first to be of lemurine affinities are found to be yet more 

 generalised, and to range with the previously mentioned animals. 

 He proposes the name Bunotheria for the order, with sub-orders 

 Creodonta, Mesodonta, Insectivora, Tillodonta, and Tseniodonta 

 (Froc. 1876, p. 88). Prof Cope has also endeavoured to equate 

 the North American Eocene to the European zones. The 

 Bridger formation of S.W. Wyoming he calls Middle Eocene, 

 characterised by Palseosyops, TUlodonta, and Dinocerata ; and 

 the Wahsatch group in N,E, New Mexico and S.W. Wyoming 



is assigned to the Lower Eocene, with Coryphodon, Tienio- 

 donta, Phenacodus, and Dlatryma. — Mr. Robert Ridgway con- 

 tributed {Proc. 1875, p. 470) a valuable monograph on the 

 North American hawks of the genus Micrastur. An examina- 

 tion of the perplexingly-various plumage shows that there is no 

 appreciable sexual difference ; there are two well-marked growth- 

 stages with plumage distinctions ; certain species are notably 

 dimorphous, some deeply rufescent, others clear plumbeous, 

 without reference to age, sex^ or stason. — Other contributions to 

 zoology include the establishment of a new genus of Procyonidoe 

 from Costa Rica, by Mr. J. A. Allen ; observations on the habits 

 of manatees kept in confinement in the Zoological Garden at 

 Philadelphia, by Dr. H. C. Chapman ; Dr. Wilder on fishes' 

 brains, and Prof. Leidy on Rhizopods, and Mr. H. K. Morrison 

 on American Noctuidse. — Dr. Isaac Lea has continued his re- 

 searches on the microscopic structure of gems, and has found 

 that in addition to the internal crystalline forms which they pos- 

 sess, there are in most gems, cavities, often tens of thousands in 

 number. — Mr. George Hay, in his chemical contributions gives 

 an account of the decomposition of stannous chloride vapour in 

 a Geissler's tube ; and of the solubility of tin, arsenic, and anti- 

 mony in concentrated nitric acid at 36° F., when the oxidation 

 is in the ratio of their several volatilities. — Prof. Persifor Frazer 

 and Dr. Koenig have been the principal contributors in geology 

 and mineralogy. — Mr. Thomas Meehan among several botanical 

 notices has given accounts of interesting hybrids, of certain insec- 

 tivorous plants, and of a certain maple tree which flourished 

 although all its leaves became reversed, so as to expose its 

 stomata to direct sunlight. The propagation of TUlandsia 

 usncoides, the epiphytic, not parasitic Florida or Spanish moss 

 was described as being principally by means of small branches 

 scattered during storms or by other means, but very rarely by 

 seeds. — An interesting observation was made on the large number 

 of cases in which double Chinese peaches of the season 1875 bore 

 two or three fruits on each flower ; thus showing their solidarity 

 with the polycarpellary Rosacese. 



Vienna 



Imperial Academy of Sciences, March 9. — On the 

 nature of the soft or half liquid state of aggregation ; on re- 

 gelation and recrystallisation, by M. Pfaundler. After dividing 

 the bodies in question into mixtures of small solid parts with 

 true liquids, soft bodies proper, containing no dissimilar parts, 

 and mixtures of the two classes, he gives a hypothesis on 

 the process of melting and the soft state. The common 

 ideal melting process, where the temperature remains the same 

 from beginning to end, is not according to fact. The mean tem- 

 perature of the body beginning to melt is about t + t' lower than 

 that of the already melted mass, if ± ^ and ± t' denote the 

 amounts of divergence of temperature of the separate molecules 

 in the solid and liquid condition. Hence the true melting point 

 is different from the temperature at the beginning and the end of 

 the melting process. M. Pfaundler extends his hypothesis to 

 soft bodies of compound nature, and to regelation and recrystal- 

 lisation. — On the difference of tension between the left ventricle 

 and the aorta, by M. (jradle. The blood pressure in the aorta 

 is usually higher than the maximal pressure in the left ventricle. 

 The difference disappears when the points of the semilimar 

 valves are torn through. — On the physical nature of vegetable 

 protoplasm, by M . Velten. The retention of form (in hair cells, 

 leaf cells, &c, ) and simultaneous mobility of particles, indicate 

 that at least two bodies with different aggregate states exist in 

 protoplasm. The dense parts do not envelop the liquid parts, 

 but solid and liquid particles are arranged beside each other in 

 small spaces. In considering the ball formation of plasma, 

 which is the principal argument for its liquid nature, M. Velten 

 distinguishes normal and abnormal ball formations j the former 

 could not prove the viscous nature of plasma, while the latter 

 unmistakeably point to a semi-liquid state of aggregation of the 

 whole body. — On nitro-glycerine and the most important nitro- 

 glycerine preparations, by M. Beckerhin. — On the condition of 

 heat equilibrium of a system of bodies with reference to gravity, 

 by M. Loschmidt. Gravitation affects only the vertical com- 

 ponent of molecular velocity, leaving the horizontal untouched ; 

 this destroys the symmetry of distribution of velocity in gases. — 

 Communications from the Mineralogical Museum of the Univer- 

 sity, by M. Schrauf. This relates to certain minerals from the 

 graphite deposits of Mugrau. 



March 16. — On the influence of temperature on galvanic con- 

 duction of tellurium, by M. Exner. Tfie alteration of conduc- 

 tivity through heat is 'due to a change of molecular structure ; 



