CE.VL/S HOLOSTICHA. ' 769 



The author scarcely concurs in regarding the linear series of minute setae 

 developed anteriorly to the five large typical anal styles in this species — referred by 

 Wrzesniowski to the genus Oxytricha — as belonging to the anal group, their contour 

 and disposition indicating rather their identity with an imperfectly developed 

 supplementary row of ventral setae. The close affinity of this type to the Amphisia 

 {Oxytricha) velox of Quennerstedt — from which species, indeed, it would appear to 

 differ most essentially, the above interpretation of the so-called anal setK being correct, 

 in the possession of two and a half instead of three complete rows of ventral setaa — 

 is fully recognized by its discoverer. 



Amphisia multiseta, Sterki. 

 Resembling ^ . ^;W;rt, but of smaller size; the ventral region concave, 

 and bearing as many as ten anal setse. 



Genus VII. HOLOSTICHA, Wrz. 



Animalcules free-swimming, not encuirassed, more or less elastic, and 

 changeable in form, oval or elongate ; the ventral surface bearing three or 

 four claw-like frontal styles, five or more anal styles, two or three uninter- 

 rupted median rows of short ventral setae, and a continuous projecting 

 border of marginal setae ; endoplast double; contractile vesicle single, 

 spherical, usually occupying a median position close to the left lateral 

 margin. Inhabiting salt and fresh water. 



The genus Holosticha has been instituted by Wrzesniowski * for the reception 

 of those species hitherto included in the genus Oxytricha, in which the ventral setae 

 form two or three uninterrupted median rows, in place of the more or less irregularly 

 scattered plan of distribution which obtains among the typical members of the 

 last-named generic group. Through the preceding genus, Amphisia, the passage 

 from Holosticha to tJroleptus and Urostyla is apparently accomplished. 



Holosticha mystacea. Stein sp. Pi,. XLIII. Fig. ii. 



Body ovate, flattened, nearly three times as long as broad, rounded and 

 widest posteriorly, the right side convex, the left concave, the upper lip 

 developed anteriorly into a bluntly rounded point ; peristome-field extending 

 backwards nearly to the centre of the body, its reflected border arcuate, 

 distinctly ciliate ; ventral setae forming two irregular, curved, central rows 

 supplemented anteriorly with a few additional styles ; marginal setae con- 

 stituting a continuous projecting border, the posterior ones longest ; anal 

 styles of medium size, not projecting beyond the posterior body margin. 

 Length 1-190" to I-144". Hab. — Fresh water. 



Identical with the Oxytricha mystacea of Stein. 



Holosticha flava, Cohn sp. Pl. XLIII. Figs. 19 and 20. 



Body elongate, flattened and band-like, flexible but not retractile, six or 



seven times as long as broad, rounded at both extremities, slightly narrower 



at the posterior one ; peristomal ciliary band fringing the anterior border and 



extending backwards to a distance of one-third of the length of the body; 



* ' Zeit^chrift fur Wissenschaftliche Zoologie,' Bd. xxix., 1877. 

 VOL. II. X 



