464 ORDER CILIO-FLAGELLATA. 



the one trailing and the other extensile and vibratile, of Anisonema, Heteromita, or 

 Heteronema. Superimposed on this we find an anterior adoral fringe of well- 

 developed cilia, the animalcule thus constituted representing an intermediate con- 

 dition or annectant type between the above-mentioned simpler Flagellata and the 

 more highly organized Ciliata. Upon this accessory ciliated fringe there appears, 

 according to Professor Clark's description, to devolve the chief task of locomotion, 

 the extended and longer anterior flagellum being used more exclusively as a tentative 

 and prehensile organ. As reported by this authority, the animalcule furthermore 

 displays much intelligence in the use of its tactile flagellum, turning and twisting it 

 about, and feeling with it in every direction with as much seeming consciousness as is 

 shown by an elephant in the control of its proboscis. No details concerning the posi- 

 tion or existence of a contractile vesicle or endoplast have yet been recorded, nor any 

 data relating to the phenomena of development and reproduction. Professor James- 

 Clark has unfortunately omitted to mention whether the endoplasm of this interest- 

 ing species is coloured green or transparent. , It structural affinities being evidently 

 nearest to Heteromma, it might be anticipated, in correlation with their structure, 

 that this element is colourless. At the same time, the development of an anterior 

 eye-like pigment-spot is more commonly associated with the chlorophyllaceous 

 forms. 



Fam. III. MALLOMONADIDJE, S. K. 



Animalcules free-swimming, bearing a single long,' terminal flagellum ; 

 entire cuticular surface covered with long, flexible, setose cilia. 



GENUS I. MALLOMONAS, Perty. 



Animalcules free-swimming, oval or elliptic, persistent in shape ; cuti- 

 cular surface indurated, clothed with long, non- vibratile, hair-like setae ; a 

 single long vibratile flagellum produced from the anterior extremity ; 

 contractile vesicle indistinctly developed. Inhabiting fresh water. 



Mallomonas Plosslii, Perty. PL. XXIV. FIGS. 72 AND 73. 



Body ovate or elliptical, slightly narrower anteriorly ; cuticular surface 

 finely shagreened or crenulate, thickly clothed with fine, hair-like setae, 

 whose length is less than that of the body ; flagellum long and slender, 

 retractile ; endoplasm vacuolar, amber colour or greenish yellow ; contractile 

 vesicle indistinct, posteriorly located. Length of body i-iooo" to 1-900". 



HAB. Marsh water. 



Having, in February 1878, obtained an animalcule from marsh-water from Le 

 Marais, Jersey, which is undoubtedly identical with the Mallomonas Plosslii of 

 Perty, the author is enabled to furnish a more accurate description and delinea- 

 tion of this singular form than has been hitherto supplied. Turning attention 

 first to the cuticular investment, its indurated character has been clearly demon- 

 strated through the discovery in abundance in the same water of the empty 

 skins, either nearly whole or in fragments with angular fractures, as left after 

 the decay of the living contents. To these cuticular fragments the hair-like seta? 

 were likewise attached, in a more or less perfect state, indicating not only their 

 rigid and durable consistence, but also their original derivation from this cuticle and 

 not from the underlying endoplasm, as was at first suspected by an examination of 

 living examples only. Perty's testimony respecting the apparently crenulated aspect 

 of the peripheral border was fully confirmed and explained by the employment of a 

 high magnifying power, when it was shown that the whole surface of the cuticle is 



