142 GENERAL HISTORY OF THE INFUSORIA. 



composition, seem to be particularly prone to decomposition, so that their 

 empty shells or their fragments are extremely seldom to be met with in 

 water abounding in loricated Monads. " In Cryptomonas pohjmorpha I have 

 repeatedly witnessed this rapid breaking up of the shell ; the margin is resolved 

 into numerous drops which separate from one another, and in the course of 

 ten or twelve minutes the lorica spreads itself out as an inconspicuous mem- 

 branous structure. Moreover, in Chonemonas hispkla a constant movement 

 is observed in the shell when the animal is about to divide, and when, as 

 almost always happens, the filaments are lost, or remain attached to the shell 

 without any connexion with the animal. Until the period of self-division 

 the connexion between the animal and shell persists, for the latter is, at its 

 origin, simply the hardened periphery of the former ; but when fission hap- 

 pens this bond is ruptui^ed and cannot be re-established, and the contained 

 animalcule, being thus set free, no longer moves ^vith the sheU, but in it, and 

 this in an uneasy, irregular manner." At p. 83 he goes on to say that in 

 Cryptomonas polymorpha internal germs (Blastien) are almost constantly 

 cognizable ; in smaller and young specimens in less abimdance. In a pool 

 containing Utricular ia in July 1848, he met with the dark green variety in 

 immense numbers, along with clear green germs from -^^"' to -^l^'", col- 

 lected in masses held together by a very dehcate peUicle, and either motion- 

 less or in active movement among the old individuals. In other varieties he 

 has seen similar germs. ThiLS, on pressing the large brown variety the germs 

 escaped as independent isolated beings. In the hyaline variety (ChiJomonas 

 Paramecium, Ehr.) he not seldom witnessed astonishingly rapid development 

 by longitudinal fission ; in one specimen the two halves remained for a con- 

 siderable time tied together by a band, which became stretched thinner and 

 thinner by the long- continued movements of the two beings until it at length 

 gave way. After moving about for some time, vital energy is lost, and probably 

 one-half of the specimens sink to the bottom of the di'op of fluid under obser- 

 vation. The germs in this hyaline variety are moreover very evident and 

 numerous. Amid the many specimens of nearly equal and minute size, 

 others much larger are not uncommon, fiuTiished with a red eye-speck. 



Schneider gives (A. N. H. 1854, xiv. p. 327) an account of Chilomonas 

 Paramecium, difi'ering much from the foregoing. He describes it as ha\dng a 

 clear nucleus with a reddish halo around it, and, although he could distin- 

 guish no contractile space, observed a reddish vesicle always in the anterior 

 extremity, and, in direct opposition to Forty's observations, states that what- 

 ever number of these animals he examined, he never observed multiplication 

 by fission (p. 133). 



In March 1848, Perty noticed Anisonema acinus (Duj.) in different stages of 

 development ; the smallest forms were evidently derived from the germs, about 

 J^'" in length, and circular ; by further growth they became elliptic, and 

 presented a larger number of internal germs ; at the same time the fibres, 

 which are so easily seen in the fuU-gro^Ti beings, were perceived with the 

 greatest difficulty in the smallest. 



Among his Thecamonadina are enumerated two genera, named Chonemonas 

 and Trijpemonas : the latter is equivalent to Ehrenberg's genus Traclielo- 

 monas ; but the former includes, besides Lagenella, two genera which the 

 Berlin systematist placed in families far removed from his Ciyptomonadina, 

 viz. CJicetoglena, placed among the Peridinicea, and Pantotrichum , classed with 

 the Cyclidina. Concerning the reproduction of these two genera, Perty has 

 some original observations. 



In some decomposing water he met with Chonemonas and Trypemonas in 

 great abundance— the greater part of a green colour with red eye-specks. 



