634 



SYSTEMATIC HISTORY OF THE INFUSORIA. 



K, Luganensis (Perty). — Large, broad, 

 slightly convex oil one side. Oral in- 

 fuudibulum deep. Rows of cilia un- 



usually numerous 

 internal corpuscles green 

 is probably a Kolpoda. 



Movements slo^\ 



1-130". It 



Genus PARAMECIUM (XXV. 329-332 ; XXIX. 25-34).— Body oblong, 

 compressed, ciliated on all sides ; mouth lateral, wdth a tongue-like process ; 

 no ^isual point. The cilia are disposed in longitudinal series ; those near the 

 mouth are sometimes longer than the others, and are alone subservient to 

 locomotion, except in two doubtful species. In P. Chrysalis the long oral ciha 

 are remarkable. The digestive cells, Ehi^enberg proceeds to say, are numerous, 

 amounting to more than a hundred, and are arranged in a berry-like manner 

 along the curved alimentary canal : in five sj)ecies they have been demon- 

 strated by artificial means, in a sixth by its usual green food. The ova in 

 two species are seen as a granular mass. In all, except one species, male 

 organs are visible. The curious star-like contractile vesicles in the larger 

 species are highly interesting, when physiologically considered, as are also the 

 little black bodies seen in P. Aiirelia. In four species complete self-division, 

 transverse and longitudinal, has been observed alternately. This genus gives 

 name to a family Parameciens or Paramecina in the systems of Dujardin and 

 Perty. 



Stein makes the uniformity in length and thickness of the cilia a character- 

 istic of Paramecium, which distinguishes it both from Loxodes and Bursaria, 

 which have larger and stronger cilia about the mouth than cover the rest of 

 the body (see p. 285). Ehrenberg's statement that those about the mouth 

 are longer than the rest requires correction ; and the instance (P. Chrysalis) 

 cited indicates only that this species is not a Paramecium. Other par- 

 ticulars requiring revision are, that Paramecia have numerous stomachs dis- 

 posed as ofi'sets upon a curved alimentary tube ; that the granular mass in 

 the interior consists of ova. The male organs referred to are the nucleus and 

 contractile vesicle or vesicles. In P. Aurelia and P. Bursaria Lachmann 

 states that the anus may be frequently recognized, in the form of a small pit 

 on the surface of the animals, even for a considerable time before and after 

 an excretion. 



In our remarks on Paistophrys we have expressed a doubt as to the inde- 

 pendent position of that genus apart from Paramecium. 



Paramecium Aurelia (M) (xxv. 329- 

 332). — Club-shaped, cylindrical, slightly 

 attenuated anteriorly. An oblique longi- 

 tudinal fold borders upon the very much 

 receding mouth. Ehrenberg states that 

 he has seen small dark crystalline bodies 

 abundant in the frontal region, which, 

 he conceives, are indications of the pre- 

 sence of nervous matter, as such cry- 

 stalline bodies often accompany it. These 

 creatures appear to him also to have the 

 sense of taste, since in the same gi*oup 

 some individuals prefer one kind of food 

 and others another. This may be ob- 

 sen-ed by mixing blue and red colours 

 together, when some will feed upon the 

 former, others upon the latter, as indi- 

 cated by the colour of the digestive 

 cells : in some the cells have a violet 

 hue. After being fed witli colour, they 

 may be dried upon glass or mica, and 



thus preserved. According to the hypo- 

 thesis of Ehrenberg, the rays of the star- 

 like vesicle are spermatic ducts, through 

 which the fluid is forced upon the ova 

 in the vicinity by the constantly repeated 

 acts of contraction of the vesicle. The 

 ducts are long, and enter the ovarium at 

 many points (see p. 312 et seq.). The 

 expiilsion of ova has frequently been ob- 

 served. The colour of these animalcules, 

 when bearing ova, is white by reliected 

 light, and yellow by transmitted ; hence 

 the names '' gold and silver little fishes," 

 so often applied to them by Joblot and 

 others ; those devoid of ova are colour- 

 less. The cilia are best seen when the 

 water is coloured ; there are from 20 to 

 52 longitudinal rows along each side of 

 the body, according to Ehrenberg, wlio 

 says that in some rows he counted from 

 GO to 70 cilia, making 3(340 organs of 



