438 THE PARASITES OF THE TERMITES. 



able proportions, of comparatively large size, apparently destitute of cils, like that 

 of Fig. 4, and many like those of Figs. 8-12, upon which no trace of these organs 

 could be detected. 



Regarding all the forms above indicated, whether ciliated or nonciliated, as 

 pertaining to Pi/rsonympha, I have supposed that the former condition probably 

 was the less mature one, and that the cils were shed as the animal assumed the 

 mature condition. 



In addition to the undulating lines of the surface of the body or the ciliary 

 investment, it would appear that Pyrsonympha possesses another accessory to 

 movement. This is usually seen, more or less distinctly, as a cord, narrow fold, 

 or doubly-contoured line, extending from one end of the body to the other. This 

 incessantly and vigorously waves in a rhythmical manner, commencing at the 

 narrow and proceeding to the broad end of the body, and quickly recommencing 

 at the former, so that the movement appears to be continuous in a circle. The 

 waves pursue a long, angular, zigzag course, in accordance with and appearing to 

 produce corresponding movements of the whole body. The motion of the undu- 

 lating cord and of the animal together impressed me with the idea of a snake in 

 a bag, making its presence obvious in active contortions. In a less active condi- 

 tion of the undulating cord of Pyrsonympha, instead of the conspicuously zigzag 

 movements of the body, it appears to produce a writhing motion. In the process 

 of dissolution of the animal, the undulating cord often appears to project to a 

 variable extent from the narrower end of the body. After death it remains more 

 or less persistent, as seen in Fig. 13. Viewed on end, while Pyrsonympha remains 

 nearly or quite stationary in position, the zigzag motion of its body, seemingly 

 due to the vigorous action of the undulating cord, gives it the appearance of a 

 rotating wheel with an angular tire. 



With the incessant zigzag motion, or the less conspicuous one of the body, less 

 vigorous but rapid undulatory movements proceed in longitudinal more or less 

 spiral lines of the surface, giving to the animal the appearance of a flame. 



A large nucleus is present in Pyrsonympha, though in the most active condi- 

 tion of the animal it is more or less obscured, and often is completely concealed 

 by other contents of the body, but becomes quite evident in dissolution of the 

 latter. It usually occupies a position in the narrower extremity in advance of the 

 middle, but occasionally is situated in the broader part. It is oval or round, and 

 often appears ovoid or pyriform, with the prolongation in advance. 



When Pyrsonympha undergoes dissolution and dies, it discharges most of the 



