766 ORDER HYPOTRICHA. 



Styles large, uncinate, three in number only ; the entire body surface from 

 the frontal series and the peristome-border backwards covered with closely 

 approximated longitudinal rows of short ventral setas ; marginal series 

 similar to the ventral setae but a little longer; five inconspicuous non- 

 projecting anal setae ; contractile vesicle spheroidal, located near the 

 centre of the left-hand border ; endoplasts two in number, with attached 

 endoplastules ; parenchyma usually filled with green chlorophyll-granules. 

 Length 1-215" to 1-144". Hab. — Fresh water. 



The fine even clothing of short setse that covers the entire ventral surface of this 

 animalcule imparts to it, in conjunction with the flexible character of its body- 

 substance, an aspect strongly suggestive of a Paramcedum or other Holotrichous 

 form, and for which, without the detection of the characteristic but not very con- 

 spicuous frontal and anal styles, it might easily be mistaken. 



Urostyla flavicans, \\'rz. 

 Body elongate-elliptical, rounded at each extremity, slightly wider 

 posteriorly, three times as long as broad ; peristome-field extending back- 

 wards to a distance of about one-third of the length of the entire body, its 

 reflected border bearing a conspicuous undulating membrane ; frontal 

 ciliary system consisting of three large uncinate styles and four or five 

 scattered setae ; ventral setae forming five somewhat oblique longitudinal 

 rows, a row each side of similar setae constituting the marginal series 

 which projects beyond the periphery only at the posterior extremity ; anal 

 styles subequal, eight in number, disposed in an oblique row, the posterior 

 one only reaching but scarcely projecting beyond the posterior border; 

 endoplasts ovate, two in number, with attached endoplastules ; contractile 

 vesicle canal-like, extending along the whole left-hand posterior peripheral 

 border. Length i-i 10". Hab. — Freshwater. 



Genus V. ONYCHODROMUS, Stein. 



Animalcules free-swimming, elliptical, encuirassed ; the cuticular surface 

 indented but scarcely flattened, peristome extending backwards to the centre 

 of the body ; ventral surface bearing three anterior oblique rows of claw- 

 like frontal styles ; from three to four similar central rows of ventral styles, 

 and five or six anal styles ; outline of body excluding the peristome-field 

 fringed with an even continuous row of small marginal setae ; endoplasts 

 multiple ; contractile vesicle single, spherical, situated near the posterior 

 angle of the peristome. Inhabiting fresh water. 



The carapace in the as yet single known species of this genus is described by 

 Stein as being less indurated than that of Euplotes, but more so than in Stylonychia. 

 From the last-named type, which it somewhat resembles, it is distinguished by the 

 linear arrangement of the ventral styles and by the total absence of caudal setae. 



Oxychodromus grandis, Stein. Pl. XLIII. Fig. 13. 



Body elliptical, almost rectangular, about two and a half times as long 

 as broad, the two lateral margins parallel, occasionally bent slightly inwards 



