Characteristics of Rotifers. 287 



from which, they escape when inconvenienced, or enfee- 

 bled by the pressure and confinement of a live box or com- 

 pressorium. Probably the greater part of this gelatinous 

 mass has no important action in keeping the colony or family 

 in union — that object seems to be effected by their tail feet, 

 which hold on to a central portion of the gelatinous matter. 

 The different members of a Gonochilus or Lacinularia group 

 are probably, in every case, all one family ; but I am not aware 

 that any one has succeeded in watching the whole process of 

 the formation of a group of Conochili, though it is not 

 uncommon to find in GonocJdlus balls individuals varying in 

 size and apparent age. When a Gonochilus group is broken 

 up, the individuals gyrate about as if utterly destitute of self- 

 control. They cannot walk or crawl, and their ciliary 

 apparatus, unlike that of the free swimmers, is not adapted 

 to execute the movements required by an independent being. 

 When in a mass, the Conochili revolve, and roll through the 

 water in various directions, and they must have some power of 

 simultaneously modifying their ciliary action, or we should 

 find them collected together on one side of a pond, or con- 

 tinually thumping against one side of a glass, which is not the 

 case. 



The Oonochilus is a free swimmer for the greater part of its 

 existence, if not for the whole of it ; but Lacinularia — which 

 I know only from report — appears to be stationary, except 

 when a young associated brood leave the parent mass, and 

 swim away in search of a fresh location. Single Lacinularians 

 are not, it is said, in the habit of making solitary journeys, 

 though they resemble very closely Megalotrocha, which is 

 described in Pritchard as ' ' white and free when young, and 

 yellowish and attached in radiating clusters when old/'' 



We may now consider Dujardin's " free swimmers," 

 the first section of which are provided with a sort of armour, 

 carapace, or cuirass. He names them from this circumstance 

 " cuirassiers." They comprehend Fteroclina, Anourella (or 

 tailless), Brachions (with tails), Lepadella, Euchlanis, Dino- 

 charis 3 8alpina, Colurella, Ratula (or rat-tail), Polyarthra, and 

 Triarthra, the former with several sword-like appendages, 

 whence Mr. G osse has given it the name of " sword-bearer," and 

 the latter with their long styles used for a jumping method of 

 locomotion. AsjAanchna, of which we shall have to speak 

 presently, belongs to this group. Dujardin describes this 

 order as composed of " animals of variable form, some round 

 and flattened, others ovoid, and either almost cylindrical or 

 compressed, but their length never being more than double 

 their breadth, covered with a membranous cuirass." [The 

 term " membranous" is objectionable, firm or hard would be 



