FRESHWATER LIFE INFUSORIA. 321 



ess. It is egg-shaped, and has the lip of its mouth prolonged on one 

 side to form a iiexible proboscis. The entire surface is banded with 

 longitudinal rows of ciha, these organs being most distinct near the 

 mouth. The general colour is faintly brown, becoming darker backwards. 

 Near the hinder extremity I have noticed a relatively large spherical 

 space, loosely occupied by a globular mass, containing a body of horse- 

 shoe form, which I take to be the nucleus. Under pressure the globular 

 mass was exj)elled, apparently by a definite passage edged with cilia. 

 Though distorted in the process, the animal quickly resumed its normal 

 shape, and, followang the proboscis, turned continuously round its centre. 

 Numerous small vacuoles are usually scattered through the interior. 

 They disappear one by one for half a minute at a time, and then 

 reappear. A constriction running lengthwise along the under-surface 

 gives the body, viewed from behind, a kidney-hke outhne, the proboscis 

 then curving towards the right. A digestive tract is plainly visible, 

 extending with finely branching channels from the funnel-shaped mouth 

 to what looks hke a distinct anal orifice. Mr. Slack's di'a wing (" Marvels 

 of Pond Life," p. 179) gives an accurate idea of the appearances 

 presented. 



Trachelocerca olor, the swan-neck animalcule, is always a pleasing 

 object, as it sails smoothly and deliberately across the field, waving this 

 side and that its long, hthe neck, sometimes backing water for a raoment, 

 or curling itself about some fragment of weed in quest of food. In length it 

 may reach l-40th of an inch ; but some specimens are much smaller. At the 

 tip of the long neck is a short projecting disc, which marks the position of 

 the mouth, and is armed with a tuft of fine cilia. Near the hinder 

 extremity, which is more or less tapering, I have noticed a contractile 

 space. Occasionally the neck appears forked, due, it has been supposed, 

 to the commencement of fission. On the other hand, it is said that 

 free-swimming Infusoria never multiply by longitudinal, only by trans- 

 verse fission. The body has its sui'face prettily chequered, a featuxe 

 which is still more distinct in an allied genus called Lacryrnaria. My 

 specimens of the latter weie got in May, in a clay-pit, amongst 

 Sphagnum. 



Colpoda cucuUus, common in stagnant water, has somewhat the 

 shape of a bean narrowed in front. The ciUa are strongest on the fore 

 part, especially at the mouth, which is situated in a depression towards 

 one side. Near the hinder end, which shows no signs of cilia, may be 

 Been a contractile space. Entire minute diatoms are often found mingled 

 Vk'ith brown or reddish matter in the food vacuoles. The animal is of a 

 rather soft consistence, and puts itself through contortions, during which 

 the greenish granules hning the transparent envelope seem in constant 

 flux. Should a portion of the body caiTying cilia become accidentally 

 detached, the fi-agmeut continues highly active hke an independent 

 being. 



Paramecium, from a Greek word meaning ohiong, comprises several 

 species which approach more or less to an elliptical figure. Stein has 

 made a special study of P. bursaria. His drawings show equal and 

 similar cOia covering the entire surface, a distinct cortical layer beneath 



