166 W. MILNE ON THE 



sluggish. Murray does not mention H. crenata as having been 

 found in South Africa. If it had been as common as H. elusa, 

 I think he was certain to have seen it. 



Habitat. — Ground, rock and tree moss, Uitenhage district (all 

 over), Umtata, Somerset East and C4rahamstown . Very common. 



Habrotrocha elusa var. vegeta. 

 PI. 12, fig. 10. 



Specific Characters. — Active, rather small, colourless. An- 

 tenna short. Neck stout and fleshy, with same outline as 

 H. elusa. Teeth three large and four small ones — possibly more. 

 Trunk plicate ; stippled, as are also the rump and foot. Rump 

 fairly heavy, without prominences. Foot of four segments ; 

 first segment long wuth straight borders. Spurs short cones 

 without interspace. Corona less than collar. Upper lip narrow, 

 rounded in front and with a slight groove. Size, l/90th inch. 



This jaunty little animal creeps fast with a short glide. It 

 usually does not take long to settle down to feed. It can be kept 

 healthy for a long time in a slide, and is generally seen actively 

 feeding. Its manner of feeding is very like that of H. plana. 

 It suddenly glides a step and is feeding again with startling 

 rapidity, and keeps on repeating this performance at short 

 intervals ; but also it may remain feeding in one position for a 

 very long time. The head is sometimes kept very steady, but 

 usually is drawn very slowly up and down, or round and back. 



The upper lip is more difficult to observe than that of H. 

 elusa, being narrower at the front, and hardly projecting over the 

 sulcus. I only once or twice got a really good view, such as 

 made clear the details. Nearly always the blackness due to 

 refraction in the sulcus obscures the parts. The tip is bent 

 downwards, and there is a cross line or ridge, a little back. 

 From the middle of this a minute groove proceeds to the front ; 

 but it would appear as if the groove does not penetrate very 

 deeply into the substance of the upper lip, and probably does 

 not reach the bottom at the tip, so that at certain angles no 

 gap is seen in front, while at others a minute gap appears. 



It nearly always feeds fully extended. 



I find this animal in fair numbers in Aberdeenshire. 



The chief differences between it and //, elusa are : The glide 



