GENUS BO DO. 255 



The genus Bodo, as originally instituted by Ehrenberg, included an heterogeneous 

 assemblage of Flagellata, some with and some without a conspicuous caudal 

 prolongation or filament, while in almost all the existence of an anterior flagellate 

 appendage was entirely overlooked. Out of the total of eight species enumerated 

 and figured by this authority in his grand work ' Die Infusionsthiere,' there can 

 be but little doubt that his Bodo socialis is identical with the Spumdia vulgaris 

 of Cienkowski, and his B. grandis with a species of Anisoncma or Heteromita. 

 The residual forms, while for the most part too imperfecdy figured and described 

 for identification, include nevertheless two conspicuous species which, having 

 formed the subject of investigation of various later authorities, are found to yield 

 sufficiently well-marked characters for generic diagnosis, and are consequently 

 here retained as typical representatives of the genus. The two in question are the 

 Bodo intcst'malis and B. ranarum of Ehrenberg as hereafter described, and around 

 which may be grouped a considerable number of animalcules that appear to exhibit 

 a fundamental correspondence in all essential points with the terms submitted in the 

 foregoing diagnosis. In no instance, as yet, has the inception of solid food by 

 any representative of the genus Bodo been actually witnessed, although one species, 

 B. Jididis, described by Professor Leidy, would appear, so far as may be decided 

 on l3y his drawings, to be capable of incepting such solid food-particles on its lateral 

 border, and therefore probably at all parts of its periphery. It is by no means 

 improbable, however, that in the majority of instances, and in a manner correspond- 

 ing to that of the Opalinidce, these endoparasitic animalcules assimilate the nutrient 

 intestinal juices of their hosts by direct absorption or endosmosis, and are thus 

 independent of a special oral area. A further investigation into the alimentary 

 capacities and more intimate structural details of the various members of this genus 

 is much to be desired. 



From the genus CenonwJias of Dujardin, with which in many respects it most 

 closely corresponds, Bodo, as here delimited, is to be distinguished by the capacity 

 and general tendency possessed by its representatives of forming a temporary or 

 permanent adhesion to neighbouring objects through the medium of its persistent 

 caudal prolongation ; Cercomo/ias, while similarly caudate, is entirely free-swimming. 

 The distinction between these two genera as here constituted is therefore precisely 

 parallel to that which obtains between the two generic groups Monas and Oikomonas. 

 With Oikomonas in its attached condition, the members of the present generic group 

 still more closely coincide, their distinction in this instance being manifested, how- 

 ever, by their retention of the caudal filament in both their free and attached 

 conditions. 



Stein, in his volume of the Flagellata, figures as representatives of the genus 

 Bodo, various species of Heteromita and Amphimoiias, as defined by Dujardin, these 

 two last-named genera being consequently though without sufficient grounds sup- 

 pressed. Typical members of the genus Bodo as here constituted do not appear 

 as yet to have fallen within the cognizance of this authority. 



Bodo intestinalis, Ehr. Pl. XIV. Fig. 14. 



Body colourless, transparent, elongate-ovate, conical or clavate, rounded 

 anteriorly, attenuate and pointed posteriorly, about three times as long 

 as broad ; tail-like filament about equalling the body in length. Length 

 1-1700". 



Hab. — Intestinal viscera of various frogs, toads, and tailed Amphibia. 



The examples referred to this species, figured and described by Perty under the 

 title of Cercomoftas intestifialis, and found in the intestine of Triton cristatns, are 

 represented with a caudal filament two or three times as long as the body. It 

 possibly represents a distinct variety. Professor Leidy has obtained the same 



