THE OPALINID CILIATE IXFUSORIANS. 



151 



of nucleus 0.0035 mm. ; width of iiiicleiis 0.0025 mm. ; diameter of 

 endospheriile 0.00125 mm.; cilia line interval, anterior 0.0025 mra.^ 

 middle 0.0042 mm., pos- 

 terior 0.0046 mm. 



This large Cepedea 

 has the dimidiata form 

 and general character. 

 It is slightly flattened. 

 The well-developed ax- 

 ial series of vacuoles 

 connects it clearly with 

 the preceding two 

 species. 



CEPEDEA OBOVOIDEA, 



new species (flg. 118). 



Fig. 115. CErEDE.\ MAD.\GASCARIENSIS, X 1 17 DIAMETERS. 



Tijpe. — United States 

 National Museum Cat. 

 No. 16516. 



Host. — Bufo lentiginosus Shaw, two infections, from Auburndale, 

 Floridi, March, 1912, N. E, Wood, collector. The type infection is 

 from United States National Museum specimen No. 48779, 63 mm. long. 

 Measurements of a good-sized individual. — Length 

 of body 0.315 mm. ; width of body 0.0975 mm. ; thick- 

 ness of body 0.0653 mm.; length and breadth of 

 nuclei, first specimen 0.0045 mm. by 0.0036 mm., sec- 

 ond specimen 0.0045 mm. by 0.004 mm., third speci- 

 men 0.0054 mm. by 0.0047 mm. ; diameter of endo- 

 spherule 0.00125 mm.; cilia. line interval, anterior 

 0.00117 mm., middle 0.0026 mm., posterior 0.004 mm. 

 This good-sized Cepedea is well demarcated from 

 other species, 1, by its broad, rounded, anterior 

 end ; 2, by its long and x^vy abundant cilia ; 3, by 

 the considerable flattening of its body. Its nuclei are 

 broadly ellipsoidal. Its endospherules are small and 

 globular. 



In progressive flattening of the body, Cepedea 

 magna., C. ohovoidea., and C. madagascariensis form 

 a series in the order named. There is no indication 

 that the flattened forms (the genus Opalina) arose 

 through these particular species, but these species 

 show the probable manner of origin of the Opalinae by a progressive 

 flattening of the body. Apparently this flattening began with the 

 anterior end of the body, even so thick a form as Cepedea dimidiata 

 form sellei^i having its anterior end wedge-shaped. 



Fig. 116. — Cepedea 

 madagascarien- 

 SIS [OP Hyper- 

 OLIDS], X 117 

 DIAMETERS. 



