ROTIFERA. 45 



a few days after he had left the flask standing open. Tlie vessel 

 which he placed near the apparatus contained on the following day 

 Vibriones and Monads, to which were soon added larger polygastric 

 Infusoria, and afterwards Rotifera.* To the organisation of this 

 higher form of Infusoria, which are always the last to appear in 

 infusions, I now proceed. 



The Rotifera are so called on account of the aggregation of their 

 cilia into circular or semicircular groups upon lobes or processes of 

 the head, which resemble rudiments of the ciliated tentacles of the 

 higher or Ciliobrachiate Polypes, f By the vibration of these cilia, 

 which occasions the appeax'ance of little wheels in rapid motion, 

 strong currents are produced in the surrounding water, and they thus 

 sei've as the instruments for locomotion and the prehension of food. 

 The body in the Rotifera is more or less elongated or vermiform. It 

 is provided, at its posterior extremity, with a pair of slender and 

 pointed claspers, protected by a sheath, into which they can be re- 

 tracted when not in use. These appendages are longer than the body 

 in some species, as the Notommata Tigris : their sheath is much elon- 

 gated and slightly annulated in the Brachioni : it is telescopiform in 

 Scaridium : both claspers and sheath are wanting only in the Anurccus. 

 The integument of the body is smooth, and never ciliated : although 

 the parasitic jointed fibres of Hygrocrocis, which attach themselves 

 sometimes to the integument of the larger species, as Notommata 

 centrura, give it that appearance. In Cluetonotus and Philodina 

 aculeata the integument is beset with stiiF bristles. The Polyarthroi 

 liave long jointed filaments, like the rays of a fish's fin, attached to 

 the sides of the body ; indicating the first rudiments of lateral 

 members. 



Not any of the species are known to secrete a silicious shell ; but 

 many of them are provided with a transparent gelatinous case, into 

 which they can contract their bodies ; thus offering another analogy 

 to the Ciliobrachiate Polypes, and also to the bivalve-sheathed Ento- 

 mostraca. The principal loricate genera are Noteus, AnurcBa, Bra- 



* XXXIV. vol. xxiii. p. 165. PI. 1. fig. 2. gives a representation of the simple 

 and cflfcctual apparatus devised by Prof. Schulze. In a glass of water containing 

 decaying SpirogyrcB Cohn first obserscd Paramcecium Aurelia, which was followed 

 in quick succession by Baker's Proteus, Lacrimaria Proteus or Trachelocerca Olor> 

 Chiloclon cHcuUatus, species of Colpoda, Euplotes of large size with green globules 

 inside, and the colourless Euplotes Charon. All these succeeded each other in the 

 course of three weeks. Then came tlie Potifcrs. 



■f Ehrenberg remarks that tlie Potifera are " Bryozoa without the power of pro- 

 pagating by gemmation." — XI. p. 384. 



