1884.] 



MICROSCOPICAL JOURNAL. 



229 



Euplotes flumipes^ sp. nov. 



Carapace irregularly suborbicular 

 or elliptical, the right-haiul body-half 

 much thickened, the anterior margin 

 truncate, often minutely crenulate or 

 beaded, the upper lip crescentic and 

 conspicuously projecting ; posterior 

 margin rounded, usually with a shal- 

 low emargination on the right-hand 

 side of the median line ; right-hand 

 border rounded, or somewhat flat- 

 tened and undulate ; the anterior and 

 posterior halves of the left-hand bor- 

 der commonly obliquely truncate in 

 opposite directions and forming cen- 

 trally a projecting and rounded angle 

 or keel-like protuberance ; peristome 

 field wide, triangular, the upper 

 right-hand corner prolonged in a sin- 

 istrally directed helicoidal curvature, 

 posteriorly extending beyond the cen- 

 tre of the ventral surface, the cilia of 

 the anterior and left-hand borders 

 large and cirrhose, the posterior por- 

 tion only of the right-hand margin 

 bearing cilia which are short and 

 fine ; styles confined to the right-hand 

 half of the ventral surface, and con- 

 sisting of six frontal, three ventral 

 and five anal ones, the extremities of 

 each of the last finely fimbriated ; 

 caudal setae four, the two on the right- 

 hand side of the median line much 

 branched ; dorsal surface convex , 

 without longitudinal furrows, mi- 

 nutely roughened and often orna- 

 mented by longitudinal rows of equi- 

 distant elevations formed of minute 

 prominences arranged in stellate clus- 

 ters ; contractile vesicle in the poste- 

 rior body-half near the right-hand 

 border ; nucleus band-like, curved, 

 very long, extending around nearly 

 the entire periphery, its extremities 

 separated by a short interval near the 

 right-hand body-margin ; anal aper- 

 ture in close proximity to the con- 

 tractile vesicle. Length of carapace 

 ^^ inch. Habitat. — Pond water, 

 near the bottom. 



The rounded angle projecting from 

 the centre of the left lateral border is 

 not always so conspicuous as in the 

 figure, (Fig. 8,) while it is occasion- 



ally even more marked. The finely- 

 fringed extremities of the anal styles 

 are diagnostic, not having been ob- 

 served in any other species of the 

 genus, and suggested the specific 

 name, feather - footed. The orna- 

 mentation of the dorsal surface, shown 

 in detail in Fig. 9, is not constantly so 

 regular as there delineated nor so 

 plainly developed. At times the stel- 

 late clusters are so prominent that 

 they obtrude themselves upon the ob- 

 server's attention ; at others the}' con- 

 sist of scattered dots or minute, elon- 

 gated elevations collected into irregu- 

 lar and imperfectly star-like pat- 

 terns. The nucleus is remarkable 

 for its great length. Its extremities 

 are usually separated by a considera- 

 ble space ; occasionally, however, 

 they are apparently in contact or even 

 overlapping. 



Conjugation takes place by the 

 union of the left-hand half of the ven- 

 tral surfaces, and reproduction, in 

 which there are some points of un- 

 usual interest, by transverse fission. 

 The first noticeable change preceding 

 the latter act is the appearance of a 

 series of cilia almost parallel with the 

 left-hand border of the peristome. 

 From the comparatively vacant space 

 over which the ventral styles are scat- 

 tered, the zooid soon gradually ex- 

 trudes fourteen new styles, a second 

 contractile vesicle appears and the 

 animalcule presents the interesting 

 aspect of an infusorian with a double 

 series of adoral cilia, two pulsating 

 vacuoles, four caudal setai and twenty- 

 eight ambulatory styles. The body 

 quite rapidly elongates until about 

 twice the length of the ordinary ani- 

 malcule, and separates across the mid- 

 dle, dividing up the twenty-eight 

 styles so that the anterior moiety pre- 

 serves the old frontal and ventral ones, 

 and takes five of the new for its anal 

 ones, extruding four fresh caudal 

 setae. The posterior portion there- 

 fore has the newly extruded frontal 

 and ventral styles, the old anal ones 

 and the old caudal sette. But before 

 final separation the posterior moiety 



