402 ORDER FLAGELLATA-EUSTOMATA. 



the substance of the anterior region of one of the lateral bands ; oral 

 aperture situated close to the flagellum, continued into a distinct though 

 minute, tubular pharynx ; contractile vesicle single, conspicuously developed, 

 located centrally close to the termination of the pharynx ; endoplast 

 occupying the median line near the pointed posterior extremity. Length 

 1-3000". Hab. — Pond water; movements slow. 



This species is identical with the Cryptoglena pigra of Ehrenberg and Stein, its 

 departure from the type of the last-named genus being made manifest more especially 

 by the two characteristic lateral colour-bands and by the possession of a single 

 flagellum only. By the addition of a second flagellate appendage the present 

 type would be rendered eligible for inclusion in the genus Cryptomonas, and would 

 be scarcely distinguishable from the young of C. ovata, as shown at PI. XXII. 

 Fig. 18. 



Genus II. CHRYSOMONAS, Stein. 



Animalcules free-swimming, illoricate, more or less ovate or elongate, 

 but flexible and changeable in form ; flagellum single, produced from the 

 centre of the anterior border ; oral aperture conspicuous, not followed 

 by a distinct pharyngeal dilatation ; endoplasm enclosing two lateral 

 coloured bands and an anteriorly situated eye-like pigment-spot ; con- 

 tractile vesicle and endoplast conspicuous. Inhabiting fresh water. 



This genus is founded by Stein * on the Monas fiavicans of Ehrenberg. Except- 

 ing for the absence of the characteristic pharyngeal excavation, it would seem to 

 closely approach Microglena. 



Chrysomonas fiavicans, Ehr. sp. Pl. XXII. Figs. 8 and 9. 



Body soft and plastic, variable in form, usually more or less elongate- 

 ovate or subcylindrical, three or four times as long as broad ; flagellum 

 single, scarcely equalling the body in length ; endoplasm enclosing two 

 anteriorly produced lateral colour-bands, which do not extend to the posterior 

 extremity, and a single eye-like pigment-spot ; contractile vesicle single or 

 double, spheroidal, and of large size, situated immediately beneath the 

 insertion of the flagellum ; endoplast minute, spherical, subcentral. Length 

 1-1720" to 1-600". Hab. — Ditch water. 



In the figures of this species given by Stein one example is represented as having 

 devoured a Navicula almost equalling itself in length, and another with two incepted 

 Chlamydomonads. MultipUcation, following upon a quiescent or encysted condition 

 as delineated by the same authority, exhibits highly interesting phenomena, one 

 zooid forming, as seen at PI. XXII. Fig. 9, a spheroidal granular matrix, within 

 which it divides, by repeated longitudinal fission, into as many as sixteen units, 

 bearing under such conditions a considerable likeness, excepting for the absence 

 of flagella, to the characteristic spheroidal colony-stocks of Syncrypta and Urogkna. 



Chrysomonas ochracea, Ehr. sp. Pl. XXII. Figs. 3-7. 

 Body variable in form, ovate, elongate or subglobose ; endoplasm clear, 

 ochreous yellow ; colour-bands centrally located, a single eye-like pigmcnt- 



* 'Infusionsthiere,' Abth. iii., 1878. 



