50 B. GRASSI AND A. SANDTAS. 



Leidy observed the species here briefly diagnosed^ but regarded 

 it, without evidence, as a young Trichonympha. 

 It also assimilates solid food. 



IV. 



MoNOCERCOMONAS TERMiTis, Grassi. ' Atti Ace. Lincei ' (5), 

 i, p. 36. 



The anterior pole of this Monocercomonas is furnished 

 with at least six very long flagella, of which one is directed 

 backwards and the others forwards. A subaxial skeletal rod is 

 present, as in Trichomonas. Average length 15ju. Solid 

 food is ingested. 



V. 



DiNENYMPHA GRACILIS, Lcidy. (PI. 20, figs. 11 — 17.) Leidy, 

 *Proc. Ac. Sci. Phil.,' 1877, p. 148. 



Body uniaxial, dissimilar at the poles, elongate, subcylin- 

 drical or vittate, often -shaped or readily becoming clavate, 

 the posterior extremity being the larger. Movements usually 

 very rapid, consisting of alternate flexion and extension in 

 the long axis of the body. Locomotion usually helicoid in 

 direction. 



The ectoplasm and endoplasm are contradistinguished only 

 by the absence of solid food-particles in the denser peripheral 

 layer. There is no trace of contractile vacuoles or mouth. 

 The nucleus is situated anteriorly, and is pyriform or clavate, 

 with the larger part posterior; there is no paranucleus. 



Flagella are absent, and their place is taken by delicate 

 undulating membranes similar to those of Trichomonas, or 

 more closely, Pararasecioides, their flagellar origin being 

 equally doubtful. The free margin of the membrane is cer- 

 tainly thickened, but as it is not united to the body by a very 

 delicate attachment, as in Trichomonas, it never becomes 

 separated so as to look like a flagellum. These apparently 

 homogeneous membranes extend from one pole to the other, 

 sometimes in straight lines, at other times so as to form one 

 or more spiral turns. When their direction is straight, or 



