OF THE ROTATORIA. 653 



places, — a circumstance that has led some obsei^ers to suggest the probability 

 of some of these lower forms being the larval states of the higher ones — a 

 view now known to be erroneous. 



Some species, especially the Eotifer vulgaris, are common wherever water 

 has remained for a little time without distui'bance, in cisterns, depressions 

 in the gutters of houses, saucers of flower-pots, and similar situations. A 

 few forms have been found in the interiors of vegetable cells. Thus Rotifer 

 vulgaris occm^s in the leaf-cells of Sphagnum, and in the clavate branches of 

 Vaucheria, feeding upon the contained chlorophyll. Notommata parasitica 

 and N. petroynyzon, found within the spheres of Volvox globator, in like 

 manner consume the little masses of green protoplasm ; whilst Notommata 

 WernecTcii, like the Rotifer, occui^s in the cells of Vaucheria. 



They often abound in the damp moss from the neighboui^hood of bogs, 

 streams, and waterfalls. But, besides these special situations, some of them 

 are to be found in almost every ditch and pond in which Lemnae, Confervae, 

 and other decaj'ing masses of vegetation abound. Sometimes they play round 

 the plants \vith incessant action, piLshing their slender bodies into every 

 recess in which food may liu'k, then backing out again as cleverly as any of 

 their larger aquatic companions can do with fin and tail, — now anchoiing 

 themselves to some projecting point by means of their flexible pseudopodia, 

 di'awing in their trochal disks with apparent alarm if any other creature 

 bnishes past their resting place with unmannerly rudeness ; then, forgetting 

 their fears, they agani evolve theii^ ciliated wheels, loosen from their anchor- 

 age, and launch away into the clear stream, displaying the varied modes of 

 progression so characteristic of different species. But it is only some of 

 the forms which indulge these vagrant habits. The higher forms, such as 

 Limnias, Melicerta, Floscularia, Lacinularia, and Stephanoceros, are quiet 

 stay-at-home matrons, at least after sowing the wild oats of their youthful 

 days. For a short time only after leaving the ovum do they roam ^vild and 

 free. They soon settle down, attaching themselves by their false feet to some 

 fixed resting place, where they spend the rest of their lives in sober tran- 

 quillity. These home-birds must be sought for amongst the stems and leaflets 

 of Ceratopliyllum, Cliara, and the water Ranunculus, more frequently occurring 

 in the clearer streams and ponds than do many of their smaller allies. 



Tnlilie the Monadina and other lower Infusoria, the Rotatoria rarely oceui^ 

 in such profusion as to coloiu' the water. It is occasionally rendered turbid 

 and milky by Brachionus Palea, which, in such cases, occurs in vast profusion. 

 BracTiionus urceolaris and B. ruhens sometimes present the same conditions. 

 Typhlina viridis, found by Ehrenberg in Egyj)t, coloured the water green . 

 Lacinularia forms small transparent gelatinous masses. Limnias annulatus 

 occasionally studs the leaves of water-plants in such number as visibly to 

 clothe them in russet broAvn ; and groups of Conochilus Volvox appear in 

 small clusters, adherent by the extremities of their pseudopodia, like a group 

 of tadpoles dipped in colourless jeUy, from which they can protnide their 

 heads or retract them at will ; but sociality does not usually characterize 

 the Rotatoria as it does Euglena and similar forms. It is only when the 

 parasitic species have taken possession of some remarkably favoiu-able 

 locaHty that they so abound as to affect the aspect of the plants on which 

 they dwell, and thus force themselves on the attention of the obseiwer. 

 Usually they must be sought for in a systematic way, without any external 

 indications whether a pool will prove productive or barren. We have, how- 

 ever, rarely been disappointed on examining the green and foul-looking 

 drainage from the manure heap in the farm-yard. Amidst its swanns of 

 Euglence we have usually found a rich supply of Rotatoria. The true micro- 



