South American Rotifera. By J. Murray. 361 



As this species may readily be confused with M. arcicata, it will 

 be best understood by emphasizing the differences. M. decipiens is 

 larger, and has a more pominent posterior lobe and deeper excava- 

 tion in front. 



The greatest structural distinction is found in the front part of 

 the dorsal plate. Whereas in M. arcuata the margin of the dorsal 

 plate runs forward till it reaches the anterior border, in M. decipiens 

 it is suddenly bent in just after crossing the border of the ventral 

 plate, and cannot be traced to the anterior border. 



The ventral plate is not constricted towards the front as it is in 

 M. arcuata. 



Habitat. — Pond in Fra(^a Eepublica, Eio ; also known in 

 Australia. 



Monostyla cochlearis sp. n. Plate XV, figs. 4oa-45&. 



Specific Characters. — Small, hyaline, flat, oval in outline, 

 anterior margins nearly straight. Dorsal plate broader, elliptical, 

 truncate in front, lateral sulcus shallow. Toe broad in basal third, 

 then suddenly contracted, and tapering to near the apex, where it 

 is shouldered and clawed. 



Description. — Length of contracted lorica 75 p., of dorsal plate 

 70 yu-, width 65 yu,, of anterior margin 40-45 fx, length of toe 35 yu,. 

 The dorsal plate is like a very short ellipse, truncate at anterior 

 end and flattened at posterior end. The segment after the dorsal 

 plate is short, broad, and rounded. 



The name cochlearis is given on account of the spoon-shaped 

 toe, with its expanded basal portion. The species is a moss- 

 dweller. 



Habitat. — Among moss from British Guiana, 1906 ; moss from 

 the summit of Papagaio mountain, Eio de Janeiro, 1912. Also 

 known in India. 



Monostyla asymmetrica sp. n. Plate XV, figs. 44«-445. 



Specific Characters. — Small, hyaline, flat, oval, rounded behind, 

 nearly straight in front. Posterior lobe short, broad. Dorsal plate 

 broader. Toe with broad base, contracted about the middle, ending 

 in two claws of unequal length. 



Description. — Length of contracted lorica 75 /a, of dorsal plates 

 65-70 /x, of toe 35 ^ ; breadth of dorsal plate 60 yit, of ventral 

 plate 50 /x, of anterior margin 40-45 /x. 



The dorsal plate is little narrower than the ventral in front. 

 The two anterior margins nearly coincide, and are nearly straight 

 No sulcus can be detected. 



The chief peculiarity is in the toe, which is forked at the end 



