March 16, 



SCIENCE. 



179 



culiar structure in the leaves of Eobinia and Ainicia; 

 and he hints that the cases of continuity in proto- 

 plasm are numerous, being found not only in the 

 pulDini of leaves, but in stems, roots, and tubers. 

 Hugo de Vries found, tliat, when fresh, uninjured 

 cells are treated with some neutral salt (say, potas- 

 sium nitrate) in progressively stronger and stronger 

 solutions, the protoplasm steadily contracts, until, 

 with a 10% solution, it api^ears as a shrunken vesicle 

 lying in the cell-cavity. In repeating these experi- 

 ments, Mr. Gardiner finds, that, in a great number 

 of instances, the contracted protoplasmic mass is con- 

 nected with the cell-wall by fine protoplasmic threads. 

 Moreover, the connecting-tlireads exhil)it nodal thick- 

 enings, each node presetiting a most perfect spherical 

 form; and in several cases he has seen the threads in 

 two adjoining cells exactly opposite each other. The 

 method of treatment for this most interesting dem- 

 onstration consists in subjecting thin, fresh sections 

 to the action of a saturated solution of picric acid, 

 washing with alcohol, and staining with aniline blue. 

 Mr. Cunningham's paper is known to us as yet only 

 through an abstract (Proc. roy. soc, Nov. 16). From 

 this abstract, which has been shortened as much as 

 is consistent with clearness, we quote the following 

 points: " The contractile organs, which are the chief 

 determinants of movement, are, throughout the en- 

 tire series of leaves, specially characterized by the 

 porous nature of their component tissues. The 

 porosity is very various in degree in different cases, 

 and, according to the extent to which it prevails, con- 

 verts the entire pulvinar organs, to a greater or less 

 degree, into masses of a spongy texture, specially 

 fitted to allow of the ready distribution of fluid con- 

 tents. In those cases where it is most highly devel- 

 oped, as in Mimosa pudica, the pulvinar parenchyma 

 is composed in greater part of iitiely porous cells, and 

 in some portions contains masses of cells, which, in 

 addition to the fine pores, are provided with one or 

 more ostiola, — rounded openings w-ith thickened 

 margins." Again: it is asserted that the rapidity 

 and magnitude of the movements in individual cases 

 bear a direct relation to the degree of development of 

 such structural features. — G. L. G. [385 



Functional differentiation in stamens. — Dr. 

 Miiller shows that some endogens possess staminal 

 differentiations in the same flower analogous to 

 those previously recorded in Melastomaceae. Species 

 of Tinnantia and Commelyna are figured, in which 

 the three upj^er stamens are shorter and more highly 

 colored than the lower ones, the quantity of pollen 

 they produce being at the same time lessened. Their 

 function is clearly to attract insects, and supply them 

 with food. The remaining stamens and the pistil are 

 so situated that insects must effect crossing while col- 

 lecting pollen from the short stamens. — {Nature, 

 Nov. 9.) w. T. [386 



ZOOLOGY. 



Coelenterates. 

 The nervous system of hydroids. — According 

 to Jickeli, the ganglion-cells of Eudendrium may be 

 seen witliout difficulty in a surface view of a tentacle 

 which has been hardened in osmic acid, and" stained 

 with picrocarmine. They are granular cells, situated 

 between the bases of tlie ectoderm-cells, and sending 

 off long processes which may join processes from adja- 

 cent ganglion-cells, or they may run to nettle-cells, or 

 in among the muscle-fibres. In some cases a process 

 from a ganglion-cell could be traced upwards, between 

 the ectoderm-cells, to a small, spindle-shaped ' sensory 

 cell' near the surface. The ganglion-cells are most 

 easily seen on the tentacles ; but they are also found on 



the body, the hypostom, and the glandular ring around 

 the base. They are especially abundant in the stem 

 of Eudendrium; and .lickeli believes that those found 

 in the hydranth are developed in the stem. On the 

 hydranth the ganglion-cells are sometimes aggregated 

 in groups, and there is an indefinite nerve- ring around 

 the base of the body. Jickeli has also succeeded in 

 detecting the ganglion-cells of Hydra, although they 

 are by no means so conspicuous as they are in Euden- 

 drium. They are less granular, the nucleus is much 

 larger, and the processes are more numerous. They 

 are found in the ectoderm of all parts of the body, 

 and they are usually situated among the groups of 

 nettle-cells. — {Zool. anz. , no. 102; Morpli. jalirb., 

 viii. 380. ) w. K. B. [387 



Histology of hydroids. — In addition to his inter- 

 esting account of the nerve-cells of Eudendrium and 

 Hydra, Jickeli describes other histological features 

 of these two genera, especially the gland-cells and 

 nettle-cells. In Eudendrium, the nettle-cells are most 

 abundant in the stem ; and he believes that this is the 

 only place where new ones are formed, and that each 

 hj'dranth receives its full share when it is formed as a 

 bud. In Hydra each nettle-capsule is almost enclosed 

 by a nucleated cell, whicli corresponds to the network 

 of muscular fibres described by Chun in the Sipho- 

 nopherae, and which sends muscular processes into 

 the layer of muscle-fibres formed by the ordinary 

 epithelio-muscular cells. 



He points out tlie fact that the various species of 

 Hydra may be identified by their nettle-cells alone. 



The paper also contains a discussion of Kleinen- 



berg's newo-muscular cell theory, and a bibliography 



of the minute anatomy of hydroids. — (Morph.jalirh., 



viii. 373.) w. K. B. [388 



Crustaceans. 



Breaks in the exoskeleton of decapod Crus- 

 tacea at the time of moulting. ^ Tlie apodemes 

 of the exoskeleton, which form the sternal ca- 

 nal enclosing the chain of nervous ganglia in the 

 Macrura, cannot be shed entire at the time of exuvi- 

 ation, as they have been said to be, without break- 

 ing the principal cords of the nervous system; and 

 F. Mocquard finds, on examining tlie exuviae of Pali- 

 nurus and the common lobster, that there is, in fact, 

 a solution of the continuity of the apodemes along 

 the median line at the time of moulting. He has 

 not examined exuviae of Brachyura, where there is 

 no proper sternal canal, but observes that the dis- 

 position of the venous sinuses necessitates tlie rup- 

 ture of the apodemes at the time of moulting. — 

 (C'o)iy5iesre?!(7«s, Jan. 1.5, 188.3.) s. i. s. [389 



Origin of the species of Ooypoda from the 

 Benin islands. — Among some specimens of Ocy- 

 poda from the Bonin islands, Mr. Ishikaw-a is quite 

 certain he sees ' specific differentiation going on 

 before our eyes ' in the varying length of the ocular 

 stylet, and some other slight differences. The speci- 

 mens are said to be closely allied to O. arenaria; but 

 the figures which accompany the paper show that 

 they are really very different, that they probably 

 belong to two well-known Pacific-ocean species (O. 

 ceratophthalma and O. cordimana), and that the 

 supposed 'stepping-stones' between the two forms 

 are only well-known variations of the former spe- 

 cies due mostly to age and sex. — {Amer. nat., Feb., 

 1883.) s. I. s. [390 



Insects, 



Habits of the basket-worm. — Prof. William 

 Macfarland called attention to two important facts in 

 thehistory of Thyridopteryx ephemeraeformis. When 

 large trees are inhabited by them, only the small ends 



