South American Rotifcra. By J. Murray, 359 



by a straight line. It is much elevated behind, and is not wrinkled 

 or faceted. Its posterior margin is scarcely perceptible, owiri;^ to 

 the obscurity of the posterior sulcus. The segment after the dorsal 

 plate is broad and rounded, and projects but little. The ventral 

 plate is about 50 yu, in width, and usually shows a constriction 

 towards the front. The lateral sulcus could only be traced in the 

 anterior half of the trunk, and appeared to die out about the 

 widest part. The edges of the toe are not quite straight, but 

 slightly undulate, as can be best seen from the small figure. The 

 claws are so slender and slight that under a low power they are 

 not seen, and the toe appears to have no end. They are parallel 

 or slightly divergent. 



Several species have been described as having two claws or a 

 forked toe, and the double claw may appear as a sport in any 

 species. None of these species at all closely resembles M. furcata. 

 Miiller's {4-7) long-lost Trichoda cornuta had the anterior margin 

 lunate, and appears to exactly resemble Ehrenberg's M. lunaris, 

 except that it has two claws. Bryce's M. hifurca (33) = Notom- 

 mata monostyleeformis Stenroos (32) is a soft-bodied non-loricate 

 a,nimal. 



I judge this to be a good species from the constancy of its 

 characters in a large number of examples examined. It is one of 

 the smallest species of the genus and family known to me. M. 

 dosterocerca is sometimes nearly as small, though normally larger 

 It may be known from all other species by the short rounded 

 form, straight anterior margin, and double claw. 



Habitat. — In several ponds in the public squares and parks of 

 Kio de Janeiro, April 1912. 



Monostyla sp. (undescribed, not figured). 



Discovered simultaneously by Mr. Harring, who will shortly 

 describe it. 



Description. — Fairly large, lorica ovate, posterior lobe very 

 prominent ; toe very long, nearly equalling the contracted lorica. 



The species closely resembles AT. lunaris, but is distinguished 

 l)y the long toe, prominent posterior lobe, and unequally excavate 

 anterior margins, the ventral being considerably deeper. 



Hctbitat. — Pond at Eio. 



Monostyla hamata Stokes (o3). Plate XV, figs. 41a to 4:1c. 



Description. — Small, oval, rounded behind, deeply excavate in 

 front ; dorsal plate broader ; toe expanded in middle and running 

 out to fine point. 



Length of contracted lorica 95 /x, of dorsal plate 75 /a, of toe 



2 B 2 



