THE liOTIFKRA. 



M. ringens, Schrank. 

 ill. V. fig. 1.) 



Mclicerta ringens .... Ebrenberg, Die Infus. 1838, p. 405, Taf. xlvi. fig. 3. 



„ .... Gosse, Trans. Micr. Soc. vol. iii. 1852, p. 58, pi. xii. figs. 1 4. 



„ Quart. J. Micr. Sci. vol. i. 1653,$. 71, pi. ii. figs. 12-27. 



„ „ . . . . „ Popular Sci. Bev. vol. i. 1862, p. 474, pi. xxvi. figs, a, b. 



,, „ .... Pritebard, Infusoria, 1861, p. 672, pis. xxxii., xxxvi., xxxvii. 



,, ,, .... Williamson, Quart. J. Micr. Sci. vol. i. 1853, p. 1, pi. i. 



figs. 14-34. 

 ,,.... Leydig, Ueb. d. Bau. d. BSderfh. 1854, p. 17. 



,, ...... Claparede, Ann. Sci. Nat. Zool. 5 S6r. t. viii. 1867, pi. iii. 



figs. 1, 2. 

 ,,.... Cubitt, Mon. Micr. J. vol. v. 1871, p. 205, pls.lxxxiii., lxxxiv. 



„ ,,.... ,, Mon. Micr. J. vol. viii. 1872, p. 8, pi. xxiii. fig. 2. 



„ „ . . . . Bedwell, Mon. Micr. J. vol. xviii. 1877, p. 214, pis. exevii. 



and exeviii. 

 „ . . . . „ J. Roy. Micr. Soc. vol. i. 1878, p. 176, pi. x. 



„ . . . . „ Mid. Nat. vol. i. 1878, p. 245. 



„ . . . . Hudson, J. Roy. Micr. Soc. vol. ii. 1879, p. fi. 



,, „ . . . . Joliet, Comptes Bendus, t. 93, 1881, pp. 748, 856. 



SP. CII. Lobes when expanded, wider tlian the tube ; chin short, extremity blunt ; 

 pellet nearly spherical. 



During the hundred and eighty years which have elapsed since Leuwenhoek dis- 

 covered M. ringens, it has been a source of delight to a long succession of observers. It 

 has had more than a dozen names given to it, and has been the subject of upwards of 

 three times as many treatises ; and no wonder, for the surprising spectacle of its whirling 

 disk captivates even those who have seen it scores of times before. 



Then the building of its tube appeals powerfully to the imagination. Here is a tiny 

 creature which, when barely an hour old, and not y^ of an inch in length, sweeps from 

 the water its food and the materials for its dwelling ; and which, at the same moment, 

 and with faultless accuracy, sorts the one from the other, and both from the mere 

 rubbish, drives away the waste, sends a stream of food down its throat, supplies 

 selected atoms to a brick-making machine in its own body, mixes them with cement, 

 moulds them into bricks, and finally (to crown the marvel) lays the bricks one by one 

 around its body in regular order, so as to form a compact and effective dwelling. 



Leuwenhoek saw, and clearly described, the laying of the pellets and the raising of 

 the tube ; but failed to see how the former were produced. Indeed, even what he did 

 discover was forgotten, so that Mr. Gosse's paper " On the Architectural Instincts of 

 Melicerta ringens " (in which the process of forming the pellets and tube was completely 

 described) roused the greatest desire in all microscopists to see this marvel for themselves. 



It is unnecessary for me to quote once more passages that are to be found in every 

 text book, but I will continue the description (interrupted at p. 08) of the various streams 

 that are set in motion by the ciliated borders of the corona, buccal funnel, and chin, 

 and briefly tell how the pellets and tube are formed. 



The main stream of waste, that rushes over the chin, has two feeble currents running 

 under the somewhat incurved edges of the buccal funnel : at the side of its banks, if I 

 may so say. Along these two currents float very minute atoms, at a comparatively 

 gentle rate, while the larger particles dash along in the main stream. As the former 

 glide along the banks of the buccal funnel they come to a notch on either side of the 

 chin, over which they slip and are then drawn by the action of connecting lines of fine 

 cilia into the ciliated cup, that lies close beneath the chin. This cup is nearly hemi- 

 spherical in shape, and is furred with fine cilia. Soon after it has been emptied of one 

 pellet, another begins to form in it, and a minute sphere of particles, generally of a 

 yellowish-brown colour, is seen whirling in the centre of the cup. As this rapidly 



