442 BULLETIN^ 120, UNITED STATES NATIONAL MUSEUM. 



favor of Metcalf's (1909) view that they are related to the Infusoria 

 Holotricha. 



Collin (1914) compares OpcHinopsis carinaria with " Opali7ia^^ 

 [Protoopalina] satumaZis. 



Metcalf (1914) describes " 6^7»«Z^7^^ " {Zelleriella) antiUiends, from 

 Bufo marinus from Jamaica, West Indies (introduced), and espe- 

 cially its double set of chromosomes; that is, 10 macrochromosomes, 

 metabolic, and 10 microchromosomes, reproductive. Comparison is 

 made of its mitosis with that of an unnamed species from Bufo 

 ludop Mills, which in the present paper is described and named 

 Opalina ohtrigronoidea maxima. 



Bnimpt (1915) reviews the work of Neresheimer (190T) and of 

 Metcalf (1909) upon the life history of the Opalinids and adds im- 

 portant comments and new data from his own studies, which we must 

 report at some length. He confirms Metcalf against Neresheimer, 

 saying that the Opalinids have microgametes, and macrogametes ; 

 Brumpt studied the phenomena of fertilization in Protoopalina intes- 

 tinalis from tadpoles of Bufo mauritanicus, in Opalina ohtngona 

 from tadpoles of Hyla orborea, in Cepedea dimidiata from tadpoles 

 of Rana esculenta, and in Opalina ranarum from tadpoles of Rana 

 temporaria ; he observed the gametes of Protoopalina intestinalis 

 from tadpoles of Bom.hina pachypa and of Bufo calaviita: and he 

 studied the phenomena of fertilization in unidentified species of Opa- 

 linids from tadpoles of Bufo Jjufo and of Discoglossus pictus. In all 

 these forms the phenomena were identical. He placed cysts of Opa- 

 linids in water for 24 hours or more before using them in experimental 

 infections. The unencysted Opalinids died, leaving only the cysts 

 alive. The Opalinids, emerging after some hours from the ingested 

 cysts when these have reached the recta of the tadpoles, rapidly divide 

 (3 to 10 longitudinal divisions) before the gametes are formed. 

 Toward the 36th hour macrogametocytes begin to appear, also micro- 

 gametes and paired couples. The number of these elements increases 

 for several days, but about the tenth day microgametes and copulat- 

 ing pairs are seldom found. 



Metcalf is confirmed in the statement that the microgametes are 

 always uninucleate, while the macrogametes are sometimes binucleate. 

 Neresheimer described encystment of the zygotes soon after conjuga> 

 tion. Metcalf did not observe this. Brumpt found cysts in tadpoles 

 of numerous species, but not immediately after fertilization. He says 

 the zygates divide repeatedly after fertilization. When the rectum 

 of the tadpole has become filled with these individuals, which have the 

 same shape as the forms in adult Anura, there comes on after some 

 weeks an epidemic of division followed by encystment, paralleling the 

 presexual phenomena among the Opalinids in the adult Anura in the 



