436 THE PARASITES OF THE TERMITES. 



Trichonympha is especially remarkable for its wonderful cloak of vibratile cils, 

 absent in Gregarina, though even Monocystis^ a related form of the earth-worm, 

 in one of its stages, is clothed with long cils, but they appear not to be vibratile. 



The absence of all trace of a vascular, nervous, and special reproductive system 

 would exclude Trichonympha from the class of worms. 



In conclusion, Trichonympha has appeared to me to be a Protozoan interme- 

 diate to the Gregarines and Infusorians, but more nearly related to the former. 



PYRSONYMPHA. 



Pursos, a flame; numpha, nymph. 



Pyrsonympha vertens. Plate 52, Figs. 1-1 1. 

 Proc. Acad. Nat. Sci. Philad. 181T, 148. 



The parasite of the Termite, distinguished by the above name, is a constant 

 associate of Trichonympha^ and occurs commonly even in much greater abun- 

 dance. It is usually not so large, but occasionally reaches a greater size. It is 

 of more delicate constitution, and more readily undergoes change and dissolution 

 after removal from the intestine of its host. Very many, indeed, undergo imme- 

 diate and rapid destruction on being transferred to the field of the microscope, 

 diffused in the fluids commonly employed in such examinations, though others 

 remain for variable periods extending to some hours with comparatively little 

 change. 



When first observed, though the animal usually remains stationary or nearly 

 so in position, its movements are so active and varied that it is difficult to obtain 

 a clear idea of its form and structure. In its rapid motion it gives one the im- 

 pression of a flaming body. It writhes about and bends and unbends in a zigzag 

 manner, while rapid undulatory movements pursue a longitudinal course in a 

 more or less spiral manner from one end to the other. (See Figs. 1-6, PI. 52.) 



When the movements of Pyrsonympha become sufficiently retarded to permit 

 a better view of its character, it usually appears of variable proportionate length 

 and breadth and of clavate form, as represented in Figs. 1-6. It exhibits no dis- 

 tinction of parts, as in Trichonympha^ and is composed of finely granular proto- 

 plasm mingled with variable proportions of coarser granules, but shows no clear 

 difi'erentiation of an integument or of ectosarc and endosarc. 



The narrower extremity of the body of Pyrsonympha, holding an advanced 

 position, is usually to a variable degree clearer or more transparent than the 

 broader portion. This commonly contains variable proportions of darkly outlined, 

 more or less angular particles, which I have viewed as solid food, consisting of 



