2 20 ORDER RHIZO-FLA GELLA TA. 



around the thicker central portion, the entire body assuming under such 

 conditions an auger-like aspect. Length 1-1760". 



HAB. The intestinal viscera of various domestic poultry. 



It is proposed to distinguish, under the above title, the organism figured and 

 described by Dr. J. Eberth in Siebold and Kolliker's ' Zeitschrift ' for the year 1861, 

 p. 98, as a new infusorial form inhabiting the intestinal viscera chiefly the caecum 

 and ileum of ducks, geese, and other domestic poultry. No name is there bestowed 

 upon it, and its accordance to a considerable extent with the Trypanosoma sanguinis 

 of Gruby, and Amoeba rotatoria of Meyer is acknowledged. Its distinction from 

 Gruby's type is clearly manifested, however, by the entire absence of the anterior 

 filamentous or tag-like appendage which forms so conspicuous a characteristic of 

 that species, and which is so prominently figured in Professor Lankester's more 

 recent delineation here reproduced. If the above-named structure in T. sangui?ris is 

 to be regarded as the analogue or rudiment of a true flagellum, it would appear 

 almost desirable to create a new generic title for the reception of the present more 

 simple form. On the other hand, however, a further investigation may not impos- 

 sibly demonstrate that both this and the preceding type are but transitional phases 

 of the same specific form, which, in common with many higher endoparasitic 

 organisms, requires the association of two distinct hosts for the full development of 

 its life-cycle, and exhibits under each condition an altogether distinct aspect. In 

 this manner it may be proved hereafter, though only submitted now as a suggestion, 

 that the flagellum- or filament-bearing Trypanomonas sanguinis, as found in the 

 blood of the frog, represents the adult condition of the more minute T. Ebcrthi, 

 which would probably be swallowed by the amphibians or their tadpoles, in com- 

 pany with the discharged faeces of the water-fowl. Or again, though this seems 

 less likely, T. sanguinis may represent the larval condition, which being devoured 

 with its host, the frog, by the water-fowl, may develop in the intestine of the latter 

 to T. Eberthi. 



Yet another interpretation may be suggested relative to the true nature and 

 significance of the present species of Trypanosoma. It is, as already stated at page 

 100, a noteworthy fact that the spermatic elements of many Amphibia correspond 

 structurally in a remarkable manner with the representatives of the present species 

 as figured by Eberth. The long, slender bodies of such spermatozoa are, as first 

 pointed out by Wagner and Leuckhart in the year 1837, and as still more fully 

 demonstrated by C. T. Von Siebold,* supplemented throughout their length by a 

 delicate frill-like border, developed straight along or in a spiral manner around it 

 throughout the whole extent or greater part of its total length. Quite recently it has, 

 moreover, been shown by Mr. Heneage Gibbes,f that the spermatozoa of the 

 Mammalia possess also, though in a less developed degree, corresponding supple- 

 mentary membranes. The high import attaching itself to this structural feature of 

 Amphibian spermatozoa just described is obvious. It necessarily renders it quite 

 possible that the form discovered by Dr. Eberth, and here provisionally accepted as 

 an independent infusorial species, may ultimately prove to be the spermatic elements 

 of frogs and other Amphibia, which, as commonly happens, have been devoured by 

 the water-fowl, and retained their vitality while passing through its viscera. 



Order II. RHIZO-FLAGELLATA, S. K. 



Animalcules progressing by means of pseudopodic extensions of their 

 sarcode after the manner of the ordinary Rhizopoda, but bearing at the same 

 time one or more flagellate appendages ; oral or ingestive area diffuse. 



* "Ueber undulirender Membranen," 'Zeit. Wiss. Zool.,' Bd. ii., 1850. 



t "On the Structure of the Vertebrate Spermatozoon," 'Quart. Jour. Mic. Sci.,' No. Ixxvi., 

 Oct. 1879. 



