4-2 



HARDWICKE'S SCIENCE-GOSSIP. 



may therefore be of service. The paste must con- 

 sist of flour and water only. The pastes sold in 

 sliops usually contain resin — tliis is fatal to the 

 production of the "eels." The paste should be 

 made thick, and boiled ; when cold it should be well 

 stirred and beaten with a wooden spoon, and this 

 process must be repealed daily to prevent the 

 growth of mould ; it is necessary, however, to 

 examine a portion, to ascertain if it contains eels. 

 In warm weather a few da.vs will generally produce 

 a plentiful supply ; in cold M^ather a longer time is 

 necessary. If the paste is too thin, they will creep 

 up the sides of the vessel, and it will be necessary 

 to place them on some thicker paste. The young 

 eels exhibit very faint traces of internal structure, 

 but as they increase in size the mouth and alimen- 

 tary canal may easily be seen ; and in the mature 

 forms the embryo young may be detected coiled up 

 within. The only preparation necessary for ob- 

 serving these forms is to place a little of the paste 

 in a little clean water, either in the live-box or on 

 an ordinary glass slip, and cover it with a piece of 

 thin ghiss. These animalcules may be kept for 

 years if a little fresh paste is occasionally added, — 



'f.k. 



The Maeki.vgs on the Battledoue Scales of 

 PoLYOMMATus Alexis. — In a paper read before 

 the Koyal Microscopic Society, Dae. G, 1S71, by 

 Dr. J. Antlion}^, the author states he had long felt 

 assured that the ordinary coarse representations of 

 the battledore scales were most imperfect and erro- 

 neous, and he had therefore proceeded to examine, 

 under various conditions, of and with the best 

 optical appliances. His observations extended over 

 scleral months, aad after the elimination of all pro- 

 bable sources of error, lie has satisfied himself that 

 the remarkable structures exliibited by these scales 

 were not in accordance with the usual representa- 

 tions of them. The objectives used were an eighth 

 and twelfth ; with these powers, and light free from 

 all obliquity, he observed the dots on tlie ribs of the 

 scale bore considerable resemblance to the glands 

 on Anagallis [as represented in tlie author's figures, 

 they bear no inconsiderable resemblance to dumb- 

 bells]. As the columns arc perpendicular to the 

 plane of the scale, the head column and base arc in 

 the same axial direction, and it is therefore neces- 

 sary to find a scale slightly Jilted up or doubled over 

 to detect the true nature of the dots. Tlie author's 

 observations are illustrated by two whole-page 

 plates of figures. — ILordhly Microscopical Journal, 

 January, 1872. 



Pleukosigiia. — At the November meeting of the 

 East Kent Natural History Society, Col. Horsly 

 continued his experiments on the effects of diiFerent 

 modes of illumination, especially as regards the 

 appearance of the lines or markings on the valves 



of Vleuros'ujma angulatiim, P. quadratum, and P. Hip- 

 pocampus, usiug a }-inch objective and transmitted 

 light. The results were so remarkable as to throw 

 doubts on the taxonomic value of the current 

 description of tlie direction of those markings. Thus 

 in the two former species the markings appeared 

 either transverse or oblique, according to the direc- 

 tion of the light (or rather according to the position 

 of valve). In P. Hippocampus the lines always 

 appeared longitudinal and transverse. This appa- 

 rently optical deception admits of a very simple 

 explanation — those forms with oblique striation, 

 the second row of dots mocking the first ; thus. 



If a valve is nearly at right angles to the 



illuminating pencil, the lines appear oblique ; if in 

 the same direction as the ray, they appear trans- 

 verse. P. Hippocampus, and all forms described as 

 having longitudinal and transverse strias, have the 



dots arranged in this manner, ; and, ol; 



course, the strise, from whatever direction they 

 receive the illuminating ray, can never appear 

 oblique. The ease with which the transverse or 

 longitudinal lines are resolved depends upon the 

 closeness of the dots ; if they are closer in a trans- 

 verse direction, the longitudinal strife are more 

 easily seen ; if in a longitudinal direction, then the 

 transverse striae are more easily seen. — P. K. 



"There is a special provision made by Nature 

 for the Mangrove. The seed drops at the proper 

 season, and is in danger of being carried away by 

 the stream from the muddy bank on which alone it 

 could grow ; but it is possessed of a small rootlet, 

 by which it can attach itself at once to the swampy 

 ground, and remain there at security. These root- 

 lets are put forth, and the stem gradually rises up 

 from the midst, and another mangrove is added to 

 the great belt of trees that lines the bank." — 

 "Beautiful Birds in Far- ojf Lands." 



"In the sunny regions of the tropics, Nature 

 seems to preserve her freshness and beauty without 

 interruption. There are no chilling winds or nip- 

 ping frosis to scatter the foliage of the forest. As 

 one leaf witliers another takes its place, so that the 

 green canopy is always full and compact. There is 

 neither autumn nor winter, but peiiDctual summer 

 reigns." — ^' Beautiful Birds in Far-off Lands." 



"It becomes possible for us to determine, through 

 comparison with those animals with whicJi we are 

 already acquainted, the homes or abodes of species 

 yet unknown to us, or, by means of an exact know- 

 ledge of its locality, to determine in prospective the 

 form and colour of a species."— ".ffzVc? Life" by 

 Dr. Brchm. 



