80 BULLETIN 120, UNITED STATES NATIONAL MUSEUM. 



the Ciliata. For fuller description of Protoopalina mitotica see Met- 

 calf (1912). 



PROTOOPALINA MEXICANA, new species. 



Type. — United States National Museum Cat. No. 16455. 



Host. — Scaphiopus muUiplicatus Cope, one abundant infection in 

 United States National Museum specimen No. 14599, 32 mm. long, 

 from Mexico, September 1, A. Duges, collector. 



Measurements of an average individual. — Length of body 0.36 

 mm. ; T\idth of body 0.06 mm. ; length of nucleus 0.0445 mm. ; width 

 of nucleus 0.013 mm. ; diameter of endospherule 0.0018 mm. ; cilia line 

 interval, anterior 0.0015 mm., middle 0.00225 mm., posterior 0.000425 

 mm. Eight massive chromosomes. 



This large Protoopalina is usually more slender than P. scaphiopo- 

 dos, P. haminondii, or P. mitotica. Its nuclei have the same form as in 

 the three species mentioned, but are in a definite telophase stage of 

 mitosis in most individuals, as is shown in figure 49, c. In this figure 

 the chromatin granules shown are only tliose in the upper half of the 

 nuclei. The endospherules of P. mexicana are much smaller than 

 those of P. scaphiopodos. In general the size of the endospherules 

 seems to be fairly constant and of safe diagnostic value for species 

 though in P. hufonis they are of considerably different sizes in dif- 

 ferent individuals. 



A very few younger individuals were found (fig. 49, a) in which 

 the nuclei were in an anaphase condition. In some of these the 

 massive chromosomes were remarkably clear (fig. 49, h) considering 

 the nature of the material and the manner of its preservation in the 

 host. In this figure the pairs of chromosomes at the opposite ends 

 of the nucleus are indicated by dotted connecting lines. That this is 

 the true pairing is shown in the preparation not only by the form 

 and the size of the several massive chromosomes, but also by the 

 somewhat irregular threads of the chromatic spindle (omitted in the 

 figure for the sake of clearness) which unite the two daughter 

 chromosomes of each pair. One could not ask for larger and clearer 

 nuclei for study than those some of the Protoopalinas present. 



PROTOOPALINA FORMOSAE, new species. 



Type. — United States National Museum Cat. No. 16456. 



Host. — Bufo melanostictus Schneider. 1 infection (out of 40 

 toads opened: 5 of the 40 toads contained other species of Opalinid), 

 from United States National Museum specimen No. 38206, 89 mm. 

 long, from Formosa, June 5, 1907; H. Sauter, collector. 



Measurements of an average individual. — Length of body 0.12 

 mm. : width of body 0.02 mm. ; length of nucleus 0.011 mm. ; width of 

 nucleus 0.0050 mm. ; diameter of endospherule 0.00175 mm. to 0.002 



