262 ORDER FLAGELLATA-PANTOSTOMATA, 



posterior two-thirds of the cavity of the lorica ; the flagellum projecting 

 considerably beyond its aperture. Length of lorica 1-1650". 

 Hab. — Pond water. 



The length of the pedicle and its oblique mode of attachment to the lorica, 

 serve to distinguish this type from any other flagellate form here described. It 

 was at first regarded by the author as a species of Bicosceca, with the animalcule in 

 a semi-contracted state, and was so described in the ' Monthly Microscopical 

 Journal' for December 187 1. The sessile mode of attachment of the zooid to the 

 bottom of its lorica, added to- the presence of a single flagellum only, indicates, 

 however, the necessity of referring it to the present genus. 



Genus II. PLATYTHECA, Stein. ^ 



Animalcules solitary, ovate, enclosed within a depressed, laterally 

 attached or decumbent lorica ; flagellum single, terminal, projecting 

 through the orifice of the lorica. 



Platytheca micropora, Stein. Pl. XI IL Fig. 54. 



Lorica ovate, depressed, transparent, not quite one and a half times as 

 long as broad, rounded and widest posteriorly, tapering towards the anterior 

 border and there perforated by an exceedingly minute pore-like orifice 

 through which the flagellum of the enclosed animalcule is protruded ; body 

 of animalcule depressed pyriform, pointed anteriorly, scarcely filling one-half 

 of the cavity of the lorica ; one or more contractile vesicles situate near 

 the anterior extremity ; endoplast posteriorly located. Length of lorica 

 1-1200". Hab. — Fresh water. 



This animalcule, while figured by Stein in the recently published volume of his 

 ' Infusionsthiere,' is referred to in the accompanying index as a somewhat doubtful 

 Flagellate type, the flagellum not exhibiting the usual characteristic vibratile 

 movements, and presenting the aspect rather of a fine setum or pseudopodium. 

 The examples delineated were found attached to the superficial cells of the roots of 

 duckweed {Lcmna). Division by fission is shown to take place within the cavity of 

 the comparatively capacious lorica. 



B. — Pantostomata-Dimastiga. 



Fam. V. DENDBOMONADID-ffi, Stein. 



Animalcules illoricate, mostly sedentary, with a more or less obliquely 

 truncate anterior border, caused by the lip-like projection of one of its 

 lateral angles ; rarely solitary, usually attached singly or in groups to 

 the extremities of a variously-branching pedicle or zoodendrium ; flagella 

 two in number, unequal, one long and one short, inserted close to each 

 other towards the centre of the anterior border ; parenchyma transparent, 

 granular ; endoplast and one or more contractile vesicles usually con- 

 spicuous, the latter mostly posteriorly located ; no distinct oral aperture, 

 food being incepted indifferently at all parts of the periphery ; increasing 

 by longitudinal subdivision. 



