670 DESCRIPTION OF ISotatoria. 



animal, inclosed but one of them ; afterwards they laid eggs, and 

 multiplied ; but it seems that then they descend the tubes of the 

 Vaucheria, and lodge themselves in new protuberances, whose deve- 

 lopment they may possibly stimulate, as galls and oak-apple s are 

 organic transformations, attributable to the influence of parasitic beings, 

 "The Rotifer vulgaris travels quite at his ease in these protube- 

 rances ; he traverses the partitions, displaces the ehromule, and 

 pushes it to the two extremities of the vesicle, so that this appears 

 darker at these parts. One day I opened a protuberance gently ; 

 I waited to see the Rotifer spring out, and enjoy the liberty so dear 

 to all creatures, even to infusorial animals, but no — he preferred 

 to bury himself in his prison, descending into the tubes of the plant, 

 and to nestle himself in the middle of a mass of gi-een matter, 

 ratlier than swim about freely in the neighbourhood of his dwelling. 

 " Some of these protuberances had greenish threads, appended 

 to their free end, and others had none ; I thought at first that these 

 threads were some mucus from within, escaped through some opening 

 which might have served the Rotifer as an entrance, but an attentive 

 and lengthened observation convinced me that in this there was no 

 solution of continuity, and that the arrival of the Rotifers in the 

 Vaucheria was not at all to be explained iu this way. How are these 

 parasitic animalcules generated within them ? This is what further 

 research has some day to show. Meanwhile I have thought that 

 it should be made known that the animalcule, found in the Vau- 

 cheria?, by Unger, was the Rotifer vulgaris of Zoologists." 



Found both in fresh and sea- water, in infusions, on the flocculent 

 matters of water plants, &,c Length l-50th to l-24th. 



EoTirEE(?) citrinus. — Body fusiform, lower part gradually attenuated 

 into a foot ; its horn-like processes elongated, eyes round, respiratory 

 tube toothed. The extremities are transparent, the middle of the 

 body of a citron colour ; it often exliibits longitudinal folds, and is 

 then less transparent. Found amongst Oscillatoiia. Length l-24th. 

 R. (?) erythraeus. — Body small, oblong, suddenly attenuated into a 

 long foot. Length 1 -240th. 



11. macrurus ( Vorticella macrura, M.) — Body transparent, ovato- 

 oblong, suddenly attenuated into a long foot; this is distinguished 

 from Aciinuriis by its small toes, horn -like processes, and suddenly- 



