D. BRYCE ON FIVE NEW SPECIES OF BDELLOID R0TIFER4. 93 



The number of these "knobs" appears to be very inconstant, 

 as in sketches made by Forstmeister Bil finger, James Murray, 

 and myself it varies from eleven to five ; and I was informed 

 by the first-named correspondent that he had met with examples 

 without any knobs at all. In such cases the species can still be 

 determined with moderate certainty from the peculiar structure 

 of the second foot joint, and the minuteness and wide separation 

 of the spurs. When the full number of prominences are present 

 they are distributed thus : the third segment of the trunk (or 

 central portion of the body) has one at either side, close to its 

 anterior boundary ; the same segment and the fourth and the 

 sixth have each one at either side near their posterior boundaries; 

 while on the dorsal side of the fifth and sixth segments there are 

 three more, arranged in a triangle (two in front on the fifth 

 and one behind on the sixth segment, the latter on the median 

 line). The fifth segment is moderately swollen laterally. The 

 lateral knobs on the sixth segment (the anal) are more nearly 

 constant than the others. Those most frequently absent are 

 the anterior pair of the third segment. 



The first foot joint has distinct lateral swellings, and is per- 

 haps swollen dorsally as well. The second joint is very short, 

 and slightly distended with thickened skin, forming a sucker- 

 like disc from the lower surface of which the three short, broad 

 toes are protrusible. The flange-like hinder margin of this 

 foot disc forms the slightly convex interspace between two very 

 minute spurs. 



When creeping about the animal is seen to have a short and 

 stout rostrum. In the feeding position the body is somewhat 

 flattened, and the dorsal longitudinal skin-folds are obliterated. 

 The trochal discs are well separated, but the head is stout and 

 the corona does not exceed the collar width. The upper lip rises 

 rather widely and high, and has a shallow central depression. 

 The rami are 14 to 16 ^t long, and are widest above the middle. 

 The anterior outer margin of each is distinctly thickened, and 

 passes gradually into a delicate winglike expansion of the ramus. 



