NO. 2032. ROTATORIA OF WASHINGTON AND VICINITY— EARRING. 401 



Lake Tanganyika, Central Africa. As no living material was available 

 it is but natural that the description is not as full as might be desired, 

 and some additional notes may be of interest. 



The body of this species is rather short and stout; the head is 

 roughly triangular in outline mth two large, short, lateral projections 

 bearing suboval ciliated lobes. A marked constriction divides the 

 head from the body, which is marked dorsally with strong longitudinal 

 folds, gradually disappearing on the sides. The foot is long and 

 wrinkled, but not jointed, sHghtly tapering and has a projecting skm- 

 fold or tail at its base. The moderately large toes are straight on 

 their inner edges, curved on the outer. 



The tubular dorsal antenna is on the posterior part of the body, 

 immediately behind the constriction, and is joined to the integument 

 in its entire length; the lateral antennae, small setigerous pimples, 

 are situated just above the foot. The two eyespots are on the ciUated 

 lobes, near their upper edges. The mouth is an oval sUt Avith its long 

 axis in the median plane; at the sides are two short papillsB tipped 

 with sensory setae. 



The mastax is of the virgate type; the fulcrum is long and straight, 

 formed of two plates joined together at the edges, so that tneir cross- 

 section is V-shaped, with the apex dorsally. The rami are roughly 

 triangular, with numerous pointed teeth on their inner edges; while 

 quite formidable looking, it is doubtful whether these teeth play any 

 part in subdividing the food; more probably they act as a sort of 

 strainer for the ''pump." The manubria are long and sUghtly in- 

 curved ; the unci have one large, nearly straight, tooth, and at their 

 bases two rudimentary teeth joined together by a thin plate. Two 

 straight rods, expanded at their dorsal ends into triangular plates, 

 pass dorso-ventrally across the mastax ; at the ventral ends they are 

 joined to the rami by muscular bands, the plate-like ends being em- 

 bedded in the dorsal wall of the mastax. As will be seen from the 

 ventral and frontal views of the trophi, these rods are not connected 

 to the manubria, nevertheless they follow these in their longitudinal 

 movements, acting apparently as a hinge. This appearance is caused 

 by their attachment to the dorsal wall of the mastax, which naturally 

 moves vnih the mallei. That these rods are of an epipharyngeal 

 nature is highly probable; their attachment to the rami is, however, 

 without a parallel among other Rotatoria. The "pumping" action 

 of the virgate mastax can be seen very clearly in this species on ac- 

 count of the transparency of the head. The rest of the alimentary 

 tract calls for few remarks; two elongate, club-shaped mastax glands 

 are in the usual position; the short esophagus leads to the globose 

 stomach, which is without separate intestine; the left gastric gland 

 is immediately behind the mastax, while the right one is crowded 

 95278°— Proc.N.M.vol.46— 13 26 



