552 ORDER HOLOTRICHA. 



am not altogether satisfied with the results, and apprehend that in some cases I have 

 not interpreted the appearances correctly." It is in connection with this amount of 

 uncertainty that for the present pertains to these organisms that they are likewise 

 here provisionally correlated with the series of Holotrichous Ciliata distinguished by 

 the possession of supplementary membraniform expansions. In Pyrsonema, which 

 attains to the largest calibre, and may not improbably therefore be a more matured 

 condition of the companion forms, the lateral margin, see PL XXVIII. Fig. 18, is 

 often so modified as to closely resemble the simple membraniform type Trypanosoma 

 sanguineus delineated at PL I. Figs, i and 2 ; while in other instances, PL XXIII. 

 Figs. 1 6 and 17, an independently mobile cord-like structure, apparently indicating 

 an undulating membrane, is distinctly manifested. 



M. C. Lespes, in a memoir on the " Organization of the European White Ant 

 Termes lucifugus" published in the ' Annales des Sciences Naturelles' for 1856, has 

 remarked that the contents of the intestines of that species consists also of a brown 

 pulp composed chiefly of a living agglomeration of Infusoria, an account of which 

 he proposed at some future time to give. This promise has not, however, so far been 

 redeemed, and it is greatly to be desired that some Continental histologist should take 

 the matter up, and ascertain whether these parasitic forms correspond with the Trans- 

 Atlantic types. A valuable suggestion respecting the examination of these and other 

 endoparasitic animalcules is contributed by Professor Leidy. Water proving too 

 thin a fluid for their preservation in a living state, a little white of egg was added, 

 and in this denser medium their normal form and characteristics were successfully 

 maintained for a considerable interval. 



GENUS I. TRICHONYMPHA, Leidy. 



Animalcules freely motile, exceedingly flexible and elastic, often con- 

 volute, mostly separable into two distinct regions consisting of a smaller 

 ovate head-like portion and a larger more or less inflated body ; cilia various 

 in length, apparently comprising three or four distinct series, one of these 

 exceedingly long and projecting considerably beyond the posterior ex- 

 tremity. Endoparasitic within the intestine of white ants. 



Trichonympha agilis, Leidy. PL. XXVIII. FIGS. 1-15. 



Body elongate-ovate or fusiform, from two to three or four times as 

 long as broad, the posterior extremity obtusely rounded or subacute, 

 according to the condition of contraction, the anterior extremity mammilli- 

 form and headlike ; cilia clothing the body forming apparently three or 

 four distinct series, the first and second shortest produced outwards and 

 downwardly from the anterior extremity ; the third longer, extending from 

 the anterior extremity through the whole length of the body, waving 

 downwards and outwards like the last ; the fourth set, longest of all, 

 extending from the apical end beneath the others in a longitudinal spiral 

 manner, beyond the posterior extremity of the body, and forming there 

 a loosely twisted fascicle with divergent ends ; oral aperture indistinct, 

 apparently taking the form of a rounded pore at the summit of the apical 

 extremity ; a narrow pharyngeal tube apparently extending thence back- 

 wards to a stomach-like dilatation which occupies the posterior two-thirds 

 of the body, and is usually filled with food-particles ; a granular nucleus- 

 like body located centrally close to the junction of the pharyngeal and food- 

 filled portion ; no contractile vesicle as yet detected. Length 1-300". 



