BDELLOID ROTIFERA OF SOUTH AFRICA. 151 



Macrotrachela smithi sp. nov. 

 PL 10, figs. 2--2a. 



Specific Characters. — Of large size and elongated. Corona 

 wider than the collar, and sulcus equal to four-fifths of the disc. 

 Upper lip a bold semicircular curve with a narrow abrupt notch 

 in froi t. Antenna short, barely equal to one-third of neck width. 

 Teeth two, well apart. Heavy rump and short foot. Spurs 

 divergent with fairly wide convex interspace, distinctive. Toes 

 three, stout. Size, l/65th inch. 



This is a large handsome animal. When fully extended, the 

 width from the rostrum to the rump very gradually and scarcely 

 perceptibly increases. The pre-anal segment is heavy, and is 

 distinctly marked o£E from the trunk. Older specimens seem to 

 creep rather laboriously, but the younger ones are active. In 

 some there were large oil globules in the stomach investment 

 extraordinarily liL'e pellets, but it was noticed that only granular 

 matter was voided. The trunk is freely ridged. 



The rostrum is stout, and has a large prominent double lamella, 

 with several long setae, some of which are motile. When feed- 

 ing, the rostrum often lies over the upper lip, and whether so or 

 tossed farther back its cilia were always seen to be in rapid 

 motion. The short antenna has three little knobs at the end, 

 and has on each side of it a swelling or protuberance. Small, 

 roundish jaws bear two teeth, far apart. The contractile vesicle 

 is large and of slow period. There are probably four segments 

 in the foot, which is short, and ends in three stout toes. The 

 second segment is extremely short, and may possibly be the spur 

 segment. Spurs are of moderate length, about equal to three- 

 fourths of the ankle width. They are widely divergent, broad 

 at the base and narrowing suddenly on the inside half-way down, 

 becoming very attenuated and ending in very sharp points. 

 There is a convex interspace. An elegant appearance is given 

 to the spurs by the graceful lines bounding them. 



There is a seta with a bulbous base on each wheel of the 

 handsome corona. The sulcus is wide and the collar prominent. 

 Corona, collar and neck are to each other as 14, 10 and 9. The 

 upper lip is semicircular with an abrupt notch in front, which 

 just breaks the bold outline. 



