I04 DAVENPORT ACADEMY OF SCIENCES. 



the anal styles and some of the frontal styles, are observed to be 

 frayed or broken up into brush-like fascicles. The dorsal surface 

 mayor may not be longitudinally ribbed, this feature, apparently, 

 not being so constant as in Eiiplotes charon. 



Reproduction takes place rapidly by transverse division. Con- 

 jugation also frequently occurs in infusions. 



EUPLOTES CARINATA StokeS. 



Body somewhat oval, evenly rounded at the extremities "and the 

 right lateral border. Left-hand border obliquely truncate in two 

 directions, forming a projecting angle. Seven frontal styles, two 

 or three ventral ones, five anal styles and four caudal setae, two 

 close together near the posterior border and two more lateral in 

 position toward the left. Peristome extending nearly to the mid- 

 dle of the body. Dorsal surface usually furrowed. Nucleus band- 

 like, curved. Contractile vescicle posterior to the middle and 

 somewhat lateral. 



Length, 60 microns. (Fig. 174, PI. XXIV.) 



A rare form in the waters of this state. Found in pond water 

 amongjiflecaying vegetation, from Washington and Monroe coun- 

 ties. 



ASPIDISCA Khrenberg. 



Oval or rounded, persistent in form, convex and usually fur- 

 rowed dorsally, flattened ventrally. Frontal, ventral and anal 

 styles present, from five to twelve of the latter. No caudal setse. 

 Peristome in the posterior region, in the left -lateral border. 

 Nucleus band-like, curved. Contractile vesicle single. 



ASPIDISCA COSTATA Du j . 



Body somewhat rounded from a dorsal or ventral point of view. 

 Convex dorsal surface with five or six longitudinal furrows. 

 When veiwed dorsally the left postero- lateral region produced 

 into a triangular, lip-like extension, indicating the oral region. 

 Usually three frontal styles, four or five scattered ventral and five 

 anal styles. Nucleus band-like, curved. Contractile vesicle usu- 

 ally in the posterior region, slightly lateral. 



Length, 35 microns. (Figs. 175-176, PI. XXIV.) 

 Aspidisca costata is found almost everywhere in infusions of 

 pond water. The oral aperture is covered by the projecting lip- 



