South American Rotifer a. By J. Murrai/. 241 



Oecistes pectv/iifer sp. ii. Plate X, figs. 14a-14c. 



Specific Characters. — Large ; corona very wide, nearly circular, 

 with no apparent gap, bearing within the disk towards the ventral 

 edge a conspicuous lobed process shaped like a hand, and towards' 

 the dorsal edge two large nipple-shaped divergent processes ; chin 

 a very prominent lobe with a pair of conical processes near its 

 apex ; body wrinkled, foot stout, about as long as trunk ; no eyes, 

 no tube or house. 



General JJescrijytion. — Length, when feeding, about 400 /x, foot 

 160 fi, diameter of corona 130 fjb, of trunk 80 ^, hand-like process 

 about 20 yLt in length and breadth. 



The corona is much wider than the trunk, as in 0. velatus and 

 Pseudoecistes. Both wreaths appear unbroken, except that the 

 secondary loses itself in the mouth. A number of ribs, four at 

 least, cross the corona. The " hand " springs from a kind of 

 papilla, and is close to the disk below, but free in its expanded 

 upper part. The nipple-shaped processes spring from large broad 

 rounded bases, and diverge outwards, upward and forward. Below 

 the great chin the neck is much constricted. The anus is very 

 high and prominent. The foot is obscurely wrinkled. 



I regret that the state of the organs prevented a clear view of 

 the jaws being had, although I subjected several specimens to 

 pressure. Four parallel teeth could be seen crossing the rami, but 

 no defined outline could be seen. 



It is a free-swimmer, and I think has no tube. When first 

 caught they swam about very violently, just as Pseudoecistes does, 

 and neither then nor in the preserved specimens did I ever see a 

 tube, nor were there any large empty tubes not otherwise accounted 

 for. I failed to detect the antennse. 



Habitat. — The water-lily pond in the Praga Eepublica, Eio de 

 Janeiro, very abundant, April 1912. 



A related form, having the hand-like process smaller and the 

 nipple-shaped processes on the corona much more developed, is 

 known in Australia. It has not yet been described. 



Order PLOIMA. 



ILLORICATA. 



The soft-bodied Ploima appear very sparingly in my collections, 

 only three of the families being represented. The explanation is 

 to be found simply in my ignorance — I did not know those families 

 well, had no books with me, and failed to get good specimens 

 conveyed to Mr. Piousselet. 



A great number of species have been recorded for South 



