ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 85 



New Fresh-water Infusoria.*— Dr. A. C. Stokes describes the 

 following new species : — 



Phacus acuminatus differs from its nearest ally, P. triquetra, in 

 having a concave lower surface and a short caudal prolongation : the 

 protoplasm contains chlorophyll-grains and two " amylaceous cor- 

 puscles." 



Oplirijoglena ovafa has a somewhat changeable body, whose anterior 

 extremity is slightly broader than the posterior ; the oral aperture is 

 placed obliquely ; no nucleus was observed ; the contractile vacuoles 

 are stellate on diastole. 



Dexioiricha centralis is readily distinguished from D. plagia 

 (Stokes) by the much greater length of the " caudal setge " ; by the 

 nearly equatorial position of the ring of cilia, and by the posterior 

 position of the contractile vacuole. 



Stentor globator is chiefly characterized by the ability to protrude 

 a soft, attenuate, tail-like prolongation of the body, by means of which 

 it can fix itself There are several stiff setse posteriorly. 



Stromhidinopsis setigera differs from the only other species, S. gyrans, 

 in the shortness of the peristomial cilia, and in the presence of long 

 fine setae on the anterior surface. 



ScypJiidia constrida is distinguished from S. inclinans by a slight 

 anterior constriction; when contracted, a projection appears from 

 the frontal border. 



Uroleptus Umnefis differs from U. longicaudatus in being shorter, in 

 the absence of a caudal prolongation, and in the undulating peristomial 

 membrane. 



Stylonychia putrina differs from all other species of this genus iu 

 its elongate elliptical form. 5'. vorax is the smallest species described ; 

 all the anal styles project beyond the posterior margin of the body ; 

 the caudal setas spring from the margin ; the left marginal setae are 

 remote from the edge of the body. 



Acinefa fluviatilis has a subtriangular lorica, quadrangular in 

 section ; lives in a tide- water creek ; has short pedicel ; single con- 

 tractile vacuole. A. lappacea : subspherical lorica ; non-adherent 

 body ; lorica produced into points where the tentacles protrude ; 

 multiple contractile vacuole ; tentacles very fine, with thickenings 

 upon them. A. alata : lorica irregularly ovate, with six or eight 

 longitudinal " wings," each of which is pierced longitudinally by four 

 pores for the tentacles ; pedicel long ; body apparently not attached 

 to lorica. 



Critical Observations on Leidy's 'Fresh-water Rhizopods of 

 North America,' and Classification of the Rhizopods in general. f — 

 Dr. G. C. Wallich closely criticizes Prof. Leidy's work, directing 

 especial attention to Difflugia, and taking the opportunity of referring 

 to observations of his own published a long time since which do not 

 appear to have been sufficiently noticed by the American naturalist. 



* Amer. Mon. Micr. Journ., vi. (1885) pp. 183-90 (14 figs.), 

 t Ann. and Mag. Nat. Hiat., xvi. (1885) pp. 317-34, 453-73. 



