GENUS DINEN YMPHA . 555 



the oral aperture undetermined, but its existence made apparent by the 

 abundant presence of incepted food-particles. Length 1-200". 



HAB. Endoparasitic within the intestine of the American white ant, 

 Termes fiavipes (Jos. Leidy). 



Like Trichonympha agilis, this animalcule is recorded by Professor Leidy as 

 usually retaining a stationary position j while stationary it at the same time frequently 

 exhibits an actively writhing or apparently twisting motion, or bends in a waving 

 manner from one extremity to the other. The consistence of the body-sarcode 

 appears to be of more delicate consistence than in the form last-described, the 

 animalcule undergoing rapid dissolution after removal from the intestine of its host, 

 and no clear distinction between the ectoplasmic and endoplasmic layers being 

 recognizable. 



In the more recent account and figures of this species given by Professor Leidy, 

 its possession of cilia, previously supposed to exist but not actually determined, is in 

 certain cases fully verified. In a very considerable number of instances, however, 

 including both smaller and full-sized examples, the most rigid scrutiny failed to 

 detect the presence of any such appendages, this peculiarity being more particularly 

 distinctive of the larger, flattened, membraniform or srrew-like zooids illustrated 

 by PI. XXVIII. Figs. 18-20. While, excepting for the absence of cilia, these 

 screw-shaped animalcules considerably resemble the accredited immature phases of 

 Trichonympha depicted at Figs. 9 and 1 1 of the same plate, the membraniform 

 example with a serrated border, represented at Fig. 18, is far more appropriately 

 comparable with the simple membraniform organism referred to the genus Trypano- 

 soma, described at pp. 218 et seq. of the preceding volume and delineated at 

 Figs. 1-6 of PI. I. According to its discoverer, Pyrsonema vertens is a constant 

 companion of Tricfwnympha, frequently occurring in even greater abundance than 

 that type. As with the last-named form, the bodies of the present species are 

 usually more or less gorged with fragments, apparently of wood fibres and cellular 

 tissue, derived from the food of their host, though the channel by which it 

 obtained access to this position remains to be defined. 



GENUS III. DINENYMPHA, Leidy. 



Animalcules freely motile, more or less elongate ; exceedingly flexible 

 and elastic, finely and uniformly ciliate throughout ; oral aperture apparently 

 existing, but its position undetermined. Endoparasitic within the intestine 

 of white ants. 



Dinenympha gracilis, Leidy. PL. XXVIII. FIGS. 21-24. 



Body highly elastic, elongate-fusiform, flattened and band-like, fre- 

 quently twisted ; cuticular surface longitudinally striate, finely ciliate 

 throughout, a tuft or crest of apparently longer cilia frequently developed 

 at the anterior extremity ; the termination of the body, when contracted, 

 or the edges of the flexures when the body is bent, exhibiting a serrated 

 aspect; parenchyma translucent, enclosing numerous globular structures, 

 including apparently a subcentral endoplast and one or more vacuolar 

 excavations ; position of oral aperture not determined, but its existence 

 predicated through the abundant presence of enclosed particles of solid food. 

 Length 1-500" to 1-350". 



G 2 



