302 Transactions. — Zoology. 



notice, uot only that another locahty may be added to then- geographical 

 distribution, but also as objects which will well repay the trouble of col- 

 lection and study. 



The first is a tube-dweUing Rotifer, Melicerta riuyens. 



This very curious animal has been well described by Gosse.* He there 

 describes the mode by which the tiny animal forms its tube, by drawing 

 from the water, by means of its cilia, any particles of solid matter which 

 might be held in suspension. These particles, he states, are deposited in 

 the ahmentary canal until there is sufficient to form a little ball, the par- 

 ticles of which become cemented together by some secretion of the animal. 

 The ball is then lifted by the head of the animal and deposited in regular 

 sequence on the rim of the tube. Having spent some time in examining a 

 number of these organisms, I found the minute description given by Gosse 

 to be generally correct, with the exception that the formation of the pellets 

 was at a much slower rate than that stated by him. The tubes occur in 

 great profusion on the finely-divided leaves of the Myriophyllurn, and are 

 easily discernible, some being ^ of an inch in length. 



The next specimen is a very puzzhng one. Probably it may be referred 

 to Plumatella repens. It is a fine species, the polypidon of which adheres 

 at the base, but it eventually becomes less aggregated, and ultimately fit'ee ; 

 coriaceous, of a dark brown almost black colour, irregularly branched, ex- 

 tending sometimes over 2 or 3 inches ; branches composed apparently of 

 tubular cells, with a cup-shaped enlargement and dilated orifices ; sometimes 

 in pairs ; walls of orifice pellucid. Tentacles yellowish white. Statoblast 

 observable in all. 



The ramulus, when adherent, short, when free, elongated. 



Statoblast elongated, oval ; annulus variable, resembling the eggs of 

 P. striata, Allm., as figured by Van Beneden, or a drawing that I have of 

 P. fruticosa, Allm. 



The general habit of the Polyp agrees with the description of Allman's 

 Plumatella repens, var. /3. 



I found the above growing plentifully on dead thistles in the swamp, 

 and brought a few specimens home with me and placed them in water. 

 The next morning I found that a number of the individuals had committed 

 suicide by the extrusion of their eggs, which I observed were floating on 

 the surface of the water. Some of the remaining individuals, however, 

 unfolded their tentacles, and enabled me to ascertain that they are not so 

 extremely sensitive to any disturbance as is usually stated in accounts of 

 P. repens. Indeed the fact of their growing so freely in such an open 

 situation in only a few inches of water would lead one to infer this. 

 " ~ * Trans. Micros. Soc, Vol. III., (1852) p. 58. ' 



