Soi'th American Rotifera. By J. Murra//. 357 



the only dotted species. 31. quadridentata is dotted, and there are 

 doubtless others. 



M.jntnctata has no close resemblance to any other species. The 

 unusual proportions of the dorsal and ventral anterior margins, the 

 deep sulcus in the anterior part, and the prominent angles or ridges, 

 are all features possessed by no other known species. 



Habitat. — In the salt-water lagoon near the Botanic Gardens, 

 Kio de Janiero, fairly abundant, April 1912. 



M. obtusa sp. n. Plate XV, figs. 37a, S7b. 



Specific Characters. — Small top-shaped, rounded behind, truncate 

 in front. Dorsal plate as broad as long, much broader than the 

 ventral. Toe with undulate margins, rounded shoulders, and short 

 claw. 



Description. — Length of contracted lorica 80 fi, of dorsal plate 

 70 fi, of toe 30-35 /a ; breadth of dorsal plate 70 //,, of ventral 

 plate 00 fjL, of anterior margin 50 fi. 



The anterior margins are both slightly convex. The dorsal is 

 wider than the ventral, which is a character unknown in any other 

 species of the family. In Cathy pna ploenensis the two margins 

 perhaps coincide ; in all others the dorsal is narrower. The 

 ventral plate has a scalloped margin ; the posterior lobe is short 

 and rounded. 



The toe is like that of Gosse's if. mollis (40), but Gosse's figure 

 shows the contracted animal of quite a different form. 



Habitat. — Pond at Gloria, Eio, several examples. 



Monostyla closteroccrca Schmarda (->i). Plate XV, figs. 39a, 2>%. 



Description. — Very small, broad, top-shaped ; dorsal plate much 

 broader, oval, truncate both ends, anterior margins moderately 

 excavate, lunate, coincident. Toe half the length of dorsal plate, 

 expanded in mid-length, then drawn out to long fine point. 

 Lateral sulcus shallow. 



Length of contracted lorica 60 fju, of dorsal plate 55 fju, width 

 60 yLt, of anterior margin 40 yit ; length of toe 30 //,. 



Schmarda, as was general among the earlier writers, does not 

 discriminate the dorsal and ventral plates, but the figure indicates 

 their separation anteriorly. He shows the anterior margin rather 

 more deeply excavate, and the angles consequently more prominent. 

 The figure is a good one for the period, and there can be no doubt 

 as to the identity of the animal, which I found generally distributed 

 over South America, with that which Schmarda found at Quito. 



The posterior segment is short, broad, and rounded. The toe 

 is narrowed a little below the base, then expanded and widest in 



Aug. 20th, 1913 2 b 



