146 THE AMERICAN MONTHLY [May 



nucleus could uot be observed even after the most care- 

 ful search and the application of the usual reagents. In 

 some samples examined all the forms under the cover 

 glass were densely vacuolated. 



Family. — Onytrichida>. S. K. 



Grenus.— Stichotricha. Perty. 



Species. — Stichotricha opisthotonoides. (fig. 18.) 



Body elongate; somewhat club shaped, the anterior 

 two thirds attenuate, three limes as long as the widest 

 part; highly elastic but persistent in shape; addicted to 

 curving backwards; peristome channel-like and extend- 

 ing from the apex to the posterior body third and there 

 curved towards the left hand body border, the peristome 

 cilia long and heavy diminishing in size as they approach 

 the oral aperture; the left hand border of the peristome 

 finely ciliated and bearing a conspicuous undulating 

 membrane, marginal setse on the anterior half of the sin- 

 istral border and on the posterior border; two oblique 

 rows of small ventral setse extending from the sinistral 

 to posterior setae; contractile vesicle conspicuous, located 

 in the posterior third and in contact with the left hand- 

 border which it extends at each expansion; nucleus, two, 

 ovate and situated one in each body half; locomotion 

 eccentric. Size 1-450 inch. 



Habitat — Old infusion of aquatic plants in ditch water. 



The writer had under observation quite a large num- 

 ber of this new form and they were all addicted to the 

 habit of bending the anterior attenuate body half back- 

 wards as if in great pain; it was this peculiar habit that 

 suggested its specific name. While in this act the undu- 

 lating membrane is thrown out from the body border to 

 a considerable distance. The writer has never seen 

 recorded that any of this genus possessed an undulating 

 membrane and believes this species stands alone in this 



