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PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 87 



opalina nucleolata siamensis 



Figure 108 



Host: Bana macrodactyla (Giinther), from Trong, Lower Siam 

 (U.S.N.M. No. 22945), and Tonking (U.S.N.M. No. 33128), both 

 specimens 44 mm, long. 



Figure lOS.—Opalina nucleolata siamensis from Rana macrodactyla: a and 6, X 75; c, X 673. 



These Opalinas have still smaller nuclei than those from R. macrodon 

 but in other regards resemble them. 



Measurements, in microns: Body (a) 265 by 162, (6) 200 by 93, (c) 

 nuclei 4.9, daughter nuclei 2.9, 3.1, dividing nuclei 4.9 by 3.3, 7 by 

 1.9, 9.7 by 2, length of cilia 12.8. 



OPAUNA OBTRIGONOIDEA Metcalf 



Figure 109 



Host: Rana palustris LeConte, tadpoles, from Woods Hole, Mass. 



Three examples of different ages, one with hind legs 6 mm. long, one 

 with the hind legs 12 mm. long, a third having four legs and with the 

 tail beginning to be absorbed, showed Opalinas in an 0. larvarum 

 stage, indicating that in this species also the narrow adults pass 

 through a broad Opalina condition in their development. 



Measurements, in microns: Body 120 by 96, 90 by 67, nucleus 8.7, 

 dividing nucleus 12 by 4.5. 



H 



