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by a tubular structure, connecting its anterior pole with the anterior tip of the 
body. The spiral rows of flagella arise from the anterior end of this structure. 
A mass of denser protoplasm is also present surrounding the tubule and the 
nucleus. An axial rod sometimes (? always) present. Type species M. porleri 
mihi. (In Leucotermes (Reticulitermes) speratus , Japan.) 
The three foregoing families belong to Grassi’s order Hypermastigina. The 
remaining family contains organisms which differ considerably from all those 
just considered. 
(4) Family Pyrsonymjphidae Grassi. 
Large or small forms. An elastic thread (the axial filament), of variable 
thickness, runs longitudinally down the body. From the anterior tip of the 
body a small number of flagellar cords start at the anterior extremity of this 
filament, and run spirally backwards attached on the surface of the body, 
becoming free as flagella at the posterior end. Spiral direction of cords 
laeotropic in all species studied. Nucleus single; variable in shape but usually 
anterior or central in position. 
Genus Pyrsonympha Leidy, 1877 (emend.). 
Body piriform, club-shaped, spindle-shaped, or screw-like: simply twisted, 
or both twisted and spirally wound. Number of flagellar cords 4 or 8. 
Subgenus I. Pyrsonympha Leidy (emend.). 
Body piriform, club-shaped, or screw-like; spirally twisted. The axial 
filament hangs in the endoplasm, its posterior end being free from the body 
wall. Type P. vertens Leidy, 1877. (In Leucotermes (Reticulitermes) fiavipes , 
N. America.) 
Subgenus II. Dinenympha Leidy (emend.). 
Body slender and wound spirally, sometimes also spirally twisted. Axial 
filament ends fixed at the posterior tip of the body, or is indistinct except 
at the anterior end. Type D. gracilis Leidy, 1877. (In Leucotermes (Reticuli¬ 
termes) flavipes, N. America.) 
As regards the systematic position of the Pyrsonymphidae I am still in 
doubt. Most recent authors—including Grassi—place this family among the 
Polymastigina: but the organisms appear to me so different in many ways 
from all the other forms in this order, that I hesitate to assign them to this 
group. It seems to me that it will be necessary to found a new order to contain 
them; but as the classification of the whole order Polymastigina is still de¬ 
fective, owing to our incomplete knowledge of many forms, I shall not propose 
a name for this suggested new order at present. 
Parasitology xm 
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