378 OHIO BIOLOGICAL SURVEY 



cliloroleucites numerous, disciform; paramylon granules of vari- 

 ous forms, at times absent; reproduction during encystment in 

 gelatinous capsules which multiply rapidly. 

 Distribution, cosmopolitan. 



TABLE OF SPECIES. 



A^ Posterior part of body more or less uncinate. 

 Bi Periplast smooth or with longitudinal striae. 



C Sides concave 1. P. anacoelus 



C- Sides convex. 



D^ Lateral margins much expanded. . 2. P. alata 



D- Lateral margins not expanded. 



E' Form circular from a lateral view ex- 

 cept posterior spike-like process. . 3. P. orbicularis 

 E- Form elongate. 



F' Dorsal area without longitudinal 



carina. . . 4. P. pleuronectes 



F- Dorsal area with longitudinal 



carina 5. P. triqueter 



B- Periplast with fine wart-like processes. . . 6. P. suecica 

 A- Posterior part of body not uncinate, the spike-like pro- 

 cess either being straight or absent. 

 Bi Periplast smooth or with longitudinal striae. 



C^ Posterior tooth-like process as long as or longer 



than the body 7. P, longicauda 



C- Posterior tooth-like process when present, 

 shorter than the body. 

 D^ Posterior end with tooth-like process. 

 El Tooth-like process approximately 



length of body. 

 E- Tooth-like process extremely short. 

 D- Posterior end without tooth-like process. 

 El Posterior end slightly constricted. 

 E2 Posterior end broadly rounded. 

 B2 Periplast with spiral striations, minute spines, or 

 course wart-like processes. 



Ci Periplast with spines or wart-likc processes, 

 but without spiral striations. 



Di Periplast covered with minute spines. . 12. P. hispidula 

 D2 Periplast covered with coarse wart-like 



processes. . . . . . 13. P. monilata 



C^ Periplast with spiral striations. 



Di Posterior end gradually narrowed to form a 



tooth-like process. . . . . 14. P. pyrum 



D- Posterior end either suddenly narrowed to 

 form tooth-like process, or process absent. 



