2714 Microscopical Society. 



which they should be referred. One main reason for our specimens being so poor is 

 that we do not collect them soon enough : they should be sought for in March ; by 

 delaying to collect them till April the specimens become wasted. I have no doubt 

 many might be met with in February in forward seasons. Haworth distinctly states 

 that Mr. Hatchett took two specimens of purpurella, in copula, in February. 



Proceedings of the Microscopical Society of London. 



January 16, 1850. — George Busk, Esq., President, in the chair. 

 A paper " On the Architectural Instincts of Melicerta lingens, an Animal of the 

 Class Kotifera," by P. H. Gosse, Esq., was read. After some preliminary observa- 

 tions, Mr. Gosse stated that the subject of the present paper was an animalcule so 

 minute as to be almost invisible to the naked eye, inhabiting a tube composed of 

 pellets, which it forms and lays one by one. " It is," to use his own words, " a mason 

 who not only builds up his mansion brick by brick, but who makes his bricks as he 

 goes on, from substances which he collects around him, shaping them in a mould 

 which he carries upon his body." This animalcule has been long known. In 1703 

 Leeuwenhoek discovered it at Delft, and described its appearance and habits in a 

 paper published in the ' Philosophical Transactions' (vol. v. 176, abridged). It has 

 since been noticed and described by various observers ; and Ehrenberg, in his great 

 work not only details its former history, but also adds many valuable observations of 

 his own. In one part, however, of his description, viz., the mode of preparing the 

 pellet of which the tube is composed, he appears to have been mistaken ; and it is 

 the principal object of this paper to point out and correct this mistake. The animal- 

 cule is found attached to the roots of Lemna, or to the narrow leaves of Chara, Ni- 

 tella, and other subaquatic plants. Its appearance is that of a tube, of a dark 

 yellowish or reddish brown hue, composed of a multitude of round pellets, set very 

 regularly, and apparently agglutinated by a cement insoluble in water. Out of this 

 tube is protruded an animalcule, exhibiting, when fully expanded, a short stem car- 

 rying two large petal-like disks set round with cilia, and two smaller leaflets opposite 

 to the former, also ciliated, and thus giving it the appearance of a flower of four un- 

 equal petals. Its most remarkable anatomical feature is a round cup-shaped cavity 

 situated below the ciliated lobes, on the ventral aspect, within the margin of which a 

 rapid rotation of cilia goes on. The rotation of the cilia of the lobes causes a current 

 which carries any extraneous substances within its influence into this cup, where they 

 are apparently consolidated. Upon adding some carmine to the water containing 

 this animalcule, the particles were seen to run in a constant stream through one of 

 the divisions of the petals, and, proceeding round a part of the body of the animal, 

 were deposited in this little cup-shaped cavity, where they were whirled about with 

 great rapidity, and formed into a kind of pellet. Imagining that this organ might 

 have something to do with the construction of the tube, and a favourable opportunity 

 occurring, Mr. Gosse watched the creature attentively, and soon had the satisfaction 

 of seeing it bend itself forward, deposit a pellet on the edge of the tube, and again 

 proceed to fill the now empty cup with another mass of particles of carmine, which, 

 when formed into a pellet, was deposited in a similar manner : this was repeated at 



