548 ORDER HOLOTRICHA. 



HAB. Salt water. Locomotion rapid, forwards or backwards in a 

 straight line, with the undulating membrane rapidly vibrating ; sometimes 

 stationary. 



Cohn* compares the contour of the animalcules of this species, with their undu- 

 lating membranes expanded, to that of small boats with their sails spread ; multi- 

 plication by transverse and longitudinal fission, but chiefly the latter, was observed. 

 The attenuate anterior extremity of the body in advance of the oral region is de- 

 scribed as being very elastic, and capable of flexure in various directions, so much so, 

 indeed, that, divested of the characteristic undulating membrane, this type would 

 closely resemble a minute Loxophyllum or Amphileptus. Cohn suggests the probable 

 identity of this species with the Vibrio verminus of O. F. Muller, and also, perhaps, 

 with the Cyclidium elongatum of Claparede and Lachmann. While there can be little 

 doubt that this latter form should be rightly referred to the genus Lembus, the 

 description and figure supplied by its describers would appear to indicate its claim 

 to separate specific recognition. No indication is given of the transverse annulations 

 of the posterior body-half, nor of a difference in calibre between the cilia that clothe 

 the general cuticular- surface and those developed along the oral furrow which is so 

 distinctly observable in Cohn's species. Muller's type, on the other hand, may be 

 more readily identified with the form upon which the new genus Proboscella is here 

 established. 



Lembus pusillus, Quennerstedtf 



Body elongate, subcylindrical, about three times as long as broad, 

 rounded at each extremity, the anterior one slightly narrower ; undulating 

 membrane extending backwards to a distance of about one-half of that 

 of the entire body, not supplemented by a fringe of conspicuously larger 

 adoral cilia ; cuticular surface striate longitudinally, evenly and finely ciliate 

 throughout; contractile vesicle postero- terminal. Length 1-900" to 1-625". 



HAB. Salt water. 



The longitudinal direction of the surface markings and smaller size of this species 

 serve to distinguish this type from that last described. 



Lembus subulatus, S. K. PL. XXVII. FIGS. 66 AND 67. 



Body elongate, subulate, four or five times as long as broad, rounded 

 and subcylindrical posteriorly, tapering gradually from the centre of the 

 body, and terminating anteriorly in a subulate, somewhat upturned point ; 

 oral aperture ventral, subcentral ; undulating membrane extending back- 

 wards from the anterior extremity to the oral aperture, continuous with a 

 conspicuous fringe of larger adoral cilia; cuticular surface exhibiting 

 neither longitudinal nor transverse striae ; endoplasm transparent, finely 

 granulate; contractile vesicle postero-terminal, endoplast spheroidal, situated 

 a little in advance of the median line. Length 1-750". 



HAB. Salt water, among decaying vegetable matter. 



This species has been recently obtained by the author in considerable abundance 

 at St. Heliers, Jersey, associated with the Bacterial gloea-like film rising to the 

 surface of sea water containing seaweeds, Polyzoa, and other organisms in an 



* "Neue Infusorien im Seeaquarium," 'Zeit. Wiss. Zool.,' Bd. xvi., 1866. 

 t ' Sveriges Infusoriefauna,' Lunds Universitets Ars-skrift, 1869. 



