THE OPALINID CILIATE INFUSOEIANS. 



137 



Subfamily Opalininae. 



We have now come to the multinucleated forms. Of these 

 are two genera ; Cepedea^ circular, or nearly so, in cross section 

 Opalina, much flattened. The Opalinae 

 may be divided into two groups : a, spe- 

 cies which are narrow and obovate, like 

 Opalina ohtrigona, and 5, species which 

 are broad, or even nearly round, as 

 Opalino. ranarwn. Cepedea is named 

 after Casimir Cepede, who has done ex- 

 tensive work upon the Ciliata Astomata 

 and whose Avork has emphasized the fact 

 that the old family Opalinidae (in the 

 broader sense) is not a natural group, 

 and that the old genus Opalina (includ- 

 ing only my Protoopalina^ Zelleriella, 

 Cepedea, and Opalina) is quite distinct 

 from the other Astomata, being in his 

 usage the only genus in the family 

 Opalinidae. 



Among the Cepedeas we find consider- 

 able intergradation and many difficul- 

 ties in demarcating species. This is even 

 more true among the Opalinas. In these 

 multinucleated forms the nuclear phe- 

 nomena give us less assistance, for in 

 many species the nuclei rest in the reticu- 

 late condition, as is characteristic of most 

 other animals and plants. As already 

 noted, the size of the nuclei varies with 

 the phj'siological condition, and if there 

 be really " primary " and " secondary " 

 nuclei, these may differ in size. All we 

 can do is to try to present the conditions 

 found and express these in a taxonomic 

 nomenclature which is admittedly tenta- 

 tive, until the life histories of the several 

 species are known, and the races, present 

 doubtless in all, or in most, species, have 

 been studied. 



Genus CEPEDEA. 



there 

 ; and 



Fig. 102. — Cepedea lanceolata, 



X 1707 (?) DIAMETERS. (AF- 

 TER Bezzenbekger, 1904.) 



X 



CEPEDEA LANCEOLATA (Bezzenberger). 



Opalina lanceolaia Bezzenbergee (1904), 

 Host. — Rana esculenta, variety chinensis Osborn, from "Asia." 

 83103—23 10 



