THE INFUSORIA CILIATA. 



365 



Fig. 16. EX- 



CHELYS FAR- 

 CIMEX. 



f)>, Contractile ve- 

 sicle n, nucleus 

 or endoplast. 



The species Enchelys farcimen, which is found in stagnant water, and is from -^ gyth to 

 of an inch in length, has the oral cilia larger than the others, and the cuticle of the bag-shaped body 

 and changeable-shaped body is soft (Fig. 1C). 



The flask-shaped, long-necked forms, with cilia over the whole body, and the 

 mouth at the end, constitute the family Trachelocercidse. Trachelocerca olor has a 

 body yi^th of an inch in length, and Jives in pond water. Its long neck and body 

 obliquely striated with cilia, the several contractile vesicles, and its double endoplast, 

 are all characteristic (Fig. 17). 



The family Ichthyophthiriidse has the oral orifice in the midst of an adhesive disc, 

 and the cilia of the oral region are setose and radiate internally. The species of the 

 only enus is parasitic on trout and salmon and the loach. The contractile vesicles 

 in the sub-globose or ovate body are numerous, and its endoplast is curved. Length, 

 ^th of an inch (Fig. 14). 



The family Colepidse contains ovate-shaped animalcules which have an indurated 

 cuticle, and the oral aperture terminal. Coleps hirtus is a good example, and it will be noticed 

 that the surface is furrowed, so as to present the appearance of being divided into numerous 

 equal quadrangular spaces. These are indurated, and the intervening furrows are soft and ciliated. 



The mouth is at one end, and the cilia near it are larger than the others, 

 and the anus is at the opposite end. These Colepidse divide transversely, 

 and Coleps hirtus, which is from ^ thyth to -g^th of an inch long, has three 

 spinous processes at its nether end. It is a common species, living in 

 pond water amongst confervas. It is a voracious animalcule, and it may 

 be seen in numbers in the neighbourhood of any dead animal or vege- 

 table matters. These it takes in with its cilia, which form currents 

 mouthwards, and it may distend its body considerably (Fig. 13). 



During the process of natural fission, the extremities retain their 

 usual aspect, but the newly-developed central area, where separation is to 

 occur, is smooth, and thus, after division, one part of each Coleps is 

 smooth, and the other like that of the parent. 



There is a group of four families of these Holotricha which is charac- 

 terised by the presence of a portion of the cuticle or ectoplasm formed 

 into a flap, which may or may not vibrate. The Ophryoglenidse have the 

 oral aperture situated at the bottom of a distinct depression in the body, 

 within which is a vibratile flap or membrane. The genus Ophryoglena has the family character, and 

 the genus Trichoda resembles an Enchelys in shape, but the mouth is led to by an ovate furrow, 

 and from its inner wall starts a vibratile flap. This genus is common in putrid infusions 

 with the Enchelys already mentioned. A second family (the Pleuronemidse) .has the membrane 

 extending in front of the oral furrow in a hood-like manner, and it is not vibratile. The third family 

 (the Lembidse) has long, vigorously-swimming, worm-shaped animalcules, and the membrane 

 forms a long crest-like border to that furrowed part of the under surface of the body which extends 

 from the front, backwards, to the oral aperture. It has large cilia along its inner border. Lenibus 

 velifer has a long spike-shaped body, narrow in front, thicker behind, where the contractile vesicle is 

 seen, and the body is covered with long cilia. Beneath, in front, is the large membraniform 

 expansion like a fin, broadest in front. The front part of the body is elastic, and can change 

 its shape, and the hinder part is rounded. They increase by cross and longitudinal division 

 (Fig. 9). 



The last family of the group has been discovered by Leidy, and its species are most extraordinary 

 looking things, and lead very remarkable lives. They are freely moving, but rarely swimming 

 animalcules, their movements being chiefly of a twisting and writhing kind. The shape is more or 

 less elongate and spindle-shaped, and the cuticle is entirely ciliate. Sometimes there are undulating 

 membranes on it. They occur as parasites within the intestine of the American White Ant (Termes 

 flavipetj). Leidy found some white ants which had their intestines, as seen through their translucent 

 abdomen, considerably distended with a brown substance, which consisted mainly of these parasites, 



Fig. 17. A, ]!, THACHELO- 



CEUCA OLOK. 

 C, cilia of the mouth 



