BDELLOID ROTIFERA OF SOUTH AFRICA. 71 



The foot is a longish one of five segments, and bears on tlie 

 penultimate segment spurs which are only just noticeably diver- 

 gent, very narrow and acuminate, with narrow straight inter- 

 space, and equal in length to the ankle. The four toes are short 

 and stumpy. 



Habitat. — Draaifontein farm ravine pools, in company with 

 P. praelonga. Found in abundance. 



When I was examining the habits and characteristics of P. 

 inopinata, I had rather a surprise on comparing my notes after 

 having examined a good many specimens. The statements as to 

 the spurs agreed fairly well, but those on the number of segments 

 in the foot were sometimes five and sometimes four, on the 

 number of the teeth sometimes three and sometimes two ; and the 

 length of the antenna was in some cases stated to be longer than 

 the neck width, and in others shorter. In some, indications were 

 noted of a triangular upper lip, in others not. It looked as if I 

 had had, inadvertently, two species under observation. That 

 there were two species turned out to be the case, but so alike 

 in general appearance, habits, size and colour, that I had not even 

 a suspicion of the fact until I noticed these conflicting details. 

 Yet they are two very distinct species. P. inopinata has the 

 spurs slightly more divergent, a longer antenna, one foot segment 

 more, a tooth more, a narrower corona and sulcus, a different 

 type of upper lip, and shorter toes. It has the flap near the anus, 

 the other has not. It is quite extraordinary to find two species 

 living together, so alike in general appearance and habits, and yet 

 so distinct in almost every detail. 



I have never met with P. acuticornis, but I think the second 

 species referred to above might be considered a variety and I give 

 a description under the name odiosa. 



Philodina acuticornis Murray, odiosa var. nov. 



PI. 4, figs. 7-76. 



Specific Characters. — Neck short, trunk narrow, cylindrical ; 

 lumbar region and foot taper gradually from trunk to spurs. 

 Foot consists of four segments. Spurs of medium length, practic- 

 ally parallel. Toes long, sharp, about equal in length, though 

 possibly back pair rather longer. Eye-spots distinct. Antenna 

 practically equal to neck width ; with longish setae. Teeth, two 



