76 



BULLETIN 120, UNITED STATES NATIONAL MUSEUM. 



1 



Measurements of an average individual. — Length of body 0.3 mm. ; 

 width of body 0.08 mm. ; length of nucleus 0.042 mm. ; width of nu- 

 cleus 0.0125 mm. ; diameter of endo- 

 spherule 0.00350 mm.; cilia line 

 interval, anterior 0.0025 mm., mid- 

 dle 0.0052 mm., posterior 0.0052 

 mm. Massive chromosomes eight 

 in number. 



This is a large species much like 

 Protoopalina intestindlis in form, 

 though somewhat more stocky. 

 The ordinary individuals have two 

 dumb-bell shaped nuclei in the 

 anaphase condition, showing eight 

 massive chromosomes in each end. 

 One individual, with nuclei of es- 

 sentially the same character, was 

 found entering upon transverse fis- 

 sion, and one other was found with 

 a single nucleus in the same dumb- 

 bell anaphase condition, a smaller 

 individual, evidently just come 

 from division. Thus it is indi- 

 cated that fission is consummated 

 while each of the two nuclei is 

 dumb-bell shaped and in an ana- 

 phase stage of mitosis. 



PROTOOPALINA HAMMONDII, new species. 



Type. — United States National 

 Museum Cat. No. 16453. 



Host. — Scaphiopus hanunondii 

 Baird, five infections, all in United 

 States National Museum material; 

 a, the type infection, from speci- 

 men No. 9915, 44 mm. long, from 

 Guanajuato, Mexico, 1877, Duges, 

 collector; h, from specimen No. 

 36365, 63 mm. long, from Beaver 

 City, Utah, May 24, 1905, G. P. En- 

 gelhardt, collector; c, from speci- 

 men No. 52157, 25 mm. long., from 

 Wyoming, Cooper, collector; d, 

 from specimen No. 8327, 32 mm. long, from Chihuahua, Mexico, Potts, 

 collector; and e, in specimen No. 52149, 19 mm. long, from Springer- 



Fio. 46. — Peotoopalina scaphiopodos, X 



460 DIAMETEKS. IN THE DISTAL END OF 

 THE ANTERIOR NUCLEUS IS A NDCLEOLOS 

 WHICH MIGHT READILY, IN THE DRAW- 

 ING, BE> MISTAKEN FOR A NINTH MACRO- 

 CHROMOSOME. 



