BDELLOID ROTIPERA OF SOUTH AFRICA. 167 



when creeping ; the want of colour ; the corona is, pro- 

 portionately, decidedly narrower ; rump has no prominences ; 

 foot has plain, straight outline ; spurs have no interspace. It 

 feeds with neck and foot fully extended, whereas //. elusa lies 

 over the foot, and always has the neck partially retracted, so 

 that each segment shows decidedly wider than the one in front. 

 Habitat. — Ground and tree moss, Umtata, and Uitenhage 

 district. 



Habrotrocha tranquilla sp. nov. 

 PL 12, figs. 11-lla. 



Specific Characters. — Large and shapely ; stoutly built. Ros- 

 trum stout with prominent double lamella. Antenna short, 

 about one-third neck width. Dental bulb large, oval. Teeth 

 seven. Trunk plicae well marked. Rump fairly heavy, narrows 

 quickly to foot. Foot narrow and short, of four segments. 

 Spurs sharp cones, divergent, and without interspace. Corona 

 slightly wider than collar ; sulcus narrow. Upper lip projects 

 over the sulcus, and has small gap in front. Size, l/60th. 

 inch. 



This is a large handsome animal, and occasionally shows the 

 merest tinge of colour. The trunk is very long, and when feeding 

 swells out like a muscular sack ; the pre-intestinal part is com- 

 paratively short, and the post-anal very short. The posterior 

 of the trunk and the rump are eccentric, raised dorsally, so that, 

 if the toes miss the catch, the posterior swings round, and at 

 times, when welLie^, it seems compelled to shoot out the foot 

 sideways. 



Of the seven teeth, four are large and three very small. The 

 corona to collar is as 13 to 10. The upper lip is fairly broad at, 

 the top and has a small gap. It projects over the sulcus, but 

 not quite so high as the outside parts of the wheels. The upper 

 half is almost oblong, and then the border bends quickly, in 

 two curves, to the collar. The front margin is somewhat like 

 that of H. elusa, but the details are more easily made out. 



I find this species in Aberdeenshire with slight variations. 

 The corona is slightly narrower, and I counted nine teeth. There 

 was a boss on the foot. I might, however, have overlooked this 

 characteristic in the South African species, as I did not pay much 



