394 BIOLOGY OF THE PROTOZOA 



8. Stichotricha (Fij?. l~o), cilia rows spiral; often tube-dwelling; 

 peristome long. 



9. Sparotricha, cilia rows spiral; peristome half the length of 

 proboscis. 



Parasitic; rows of cilia spiral. 



10. Kerona. 



Family 3. Pleurotrichidse, Biitschli. — In these forms the anal cirri 

 are invariably ])resent with from 5 to 8 frontal cirri and 1 or 2 

 rows of marginal cilia. Ventral cilia may be present in broken rows. 



The posterior end is tail-like in the genus: 



1. Urosoma, in all other genera a distinct tail is absent. 

 The peristome is ver\' narrow in the genera: 



2. Actinoiricha, with 5 anterior ray-like spikes (membranelles). 



3. (ionostomum, no anterior spikes; with 3 caudal cirri. 

 The peristome is wide in the genera : 



4. Gastrostyla; with flexible body, broken rows of ventral cilia, 



5. OxytrJcha (Fig. 175), with 8 frontals, 5 ventral cirri, and short 

 caudal cirri. 



6. Stylonychia; marginal cilia broken posteriorly; 3 caudal cirri. 



7. Pleurotricha (Fig. 176); marginal cilia unbroken posteriorly; 

 anals 3 and 2. 



8. Onychodrovivs (Fig. 172); both ends truncate; 5 anals in line; 

 large forms. 



9. Hisirio (Fig. 175), marginal cilia unbroken; 5 anals in line; 

 small forms. 



Family 4. Psilotrichidse, Biitschli.— Here the frontal and ventral 

 cirri are much reduced and ventral cilia are entirelx' absent. In the 

 genus Balladina there are heavy bristle-like marginal cirri and one 

 row of ventral cirri, while in the genus Psilotricha (Fig. 176, D) 

 there is no regularity in the arrangement of cirri wdiich are scattered. 



Family 5. Euplotidse, Fhrenberg, Stein. — In this family cilia are 

 entirely replaced by cirri in regular arrangement of frontals, mar- 

 ginals, ventrals and anals, the latter in some cases becoming highly 

 developed and powerful, uniting with ventrals or caudals to form 

 a complex series of springing organs. Giant cirri are not developed 

 in the genera: 



1. Certesia, with 11 left marginal cirri, and 11 frontal-^'entral 

 cirri. 



2. Ewplotes (Fig. 176), wdth 4 cirri on the posterior margin and 

 9 to 10 frontal-ventral cirri. 



Giant cirri are present in the genera: 



3. Diophrys, with 3 giant posterior, and 7 to 8 frontal-ventral 

 cirri. 



4. Uronychia (Fig. 107, p. 225), with 7 to 9 giant posterior cirri. 

 Family 6. Aspidiscidse, Stein. — In this family the individuals are 



comparatively small and are characterized by a peculiar sculpturing 



