308 ORDER FLAGELLATA-PANTOSTOMATA. 



equal to or even exceeding itself in size being indiscriminately seized and pressed 

 within the substance of its yielding reticulate body-sarcode. In one instance, Mr. 

 Carter figures a large Croneuula thus incepted, while in another, PI. XIX. Fig. 17, 

 the animalcule has enclosed the central portion of a filament of Oscillatoria, the two 

 ends of which are protruding from the opposite poles of the creature's body. Although 

 the evenly vacuolar or reticulate character of the parenchyma or endoplasm of 

 Ca/Iodicfyon would appear to find no exact counterpart among the ordinary repre- 

 sentatives of its class, a near approach in this respect obtains in Noctiluca and 

 Leptodiscus among the Stomatode Flagellate forms, and in Tracheliiis and Loxodes 

 among the Ciliata. Such an open vacuolar character of the parenchyma would seem 

 to obviate the necessity for a contractile vesicle, the presence of which structure 

 Mr. Carter was unable to detect. 



Genus II. TRICHOMONAS, Donne. 



Animalcules free-swimming, soft and plastic, ovate or subfusiform, 

 bearing at the anterior extremity two long subequal flagella, a third 

 supplementary one depending from the posterior extremity ; a toothed or 

 lobate undulating membrane developed down one lateral border, which 

 presents under insufficient magnifying power the aspect of a fringe of 

 cilia ; no distinct oral aperture. Habits endoparasitic. 



The illustrations of Trichomonas batrachoriim given by Stein in the third volume 

 of his ' Infusionsthiere,' though unaccompanied by any descriptive text, have necessi- 

 tated not only the formulation of a new generic diagnosis, but also the transfer of 

 the genus from the monomastigate to tlie polymastigate section of the Flagellata. 

 As originally described by Donne and embodied in the works of Dujardin and Perty, 

 Trichomonas was represented as possessing a single anteriorly situated flagellum 

 only, supplemented on one lateral border by a conspicuous fringe of cilia. As now 

 shown by Stein, in the case at all events of the above-named species, there are no 

 less than three flagellate appendages, while the presumed lateral fringe of cilia is 

 found to be a delicate notched undulating membrane, closely resembling the 

 membraniform border that constitutes the sole organ of locomotion in the genus 

 Trypanosoma. An oral aperture, or rather the presumed position of such a structure, 

 is indicated in one of Stein's figures, though by no means with sufficient distinctness 

 to permit of the acceptance of the organism as an undoubted stomatode type. Such 

 being the case, its provisional retention among the ordinary Pantostomata has been 

 decided on. 



Trichomonas batrachorum, Perty. Pl. XIX. Figs. 30-32. 



Body subfusiform, widest centrally, pointed at each extremity, but most 

 attenuate posteriorly, two or three times as long as broad ; two long slender 

 flagella produced from the apex of the anterior extremity, a similar single 

 one apparently originating at a little distance from the posterior termination ; 

 a more or less conspicuous toothed or lobate undulating membrane developed 

 down one lateral border, and a raised keel-like line down the opposite one ; 

 endoplast anteriorly located ; contractile vesicle situated at a short distance 

 from the posterior extremity. Length 1-2000" to 1-640". 



Hab. — Intestinal canal of the common frog and toad. 



The above diagnosis and accompanying illustrations of this species are drawn 

 up and reproduced from the excellent figures of the type included in Stein's lately 

 issued volume. In the absence of the forthcoming descriptive text, one or two 



