60 BULLETIN 120, UNITED STATES NATIONAL MUSEUM. 



two pear-shaped nuclei were seen lying far apart in the body and 

 connected by a very long thread. No nuclei were found in an ana- 

 phase of mitosis, so that there was no favorable opportunity for de- 

 teiminini!: the choniosome number. Raff figures spherical nuclei, 

 but her figures are small and may not be intended to show detail. 



This species is very similar to P. piformis, but its nuclei, except 

 of course those in active division, are resting in a much later stage 

 of mitosia, each of the two being elongated preparatory to entering 

 on the next mitosis, while in P. flUformis the last mitosis is not yet 

 completed, the still united daughter nuclei being each in an anaphase 

 stage. The two species seem clearly distinct because of this differ- 

 ence in the mitotic phase of their resting nuclei, and because of the 

 ditTerence in the number of massive chromosomes. 



Specimens of P. tenuis have been deposited Avith the United States 

 National Museum as Cat. No. 16646. 



PROTOOPALINA AFRICANA, new species (flR. ?>^k p. 61). 



T7/pe.—Umted States National Museum Cat. No. 16447. 



Host. — Rana crassijjes Buchholz and Peters, one infection, fi-om 

 United States National Museum specimen No. 48852, 55 mm. long, 

 from Kribi, the Cameroons. This Rana was received from the 

 Museum of Comparative Zoology at Cambridge, Massachusetts. 



Measurements of ah ordinary individual. — Length of body 0.24 mm. ; 

 width of body 0.028 mm. ; length of nucleus, one specimen 0.0129 mm., 

 second specimen 0.0102 mm. ; width of nucleus, first specimen 0.00424 

 mm., second specimen 0.0035 mm. ; length of endospherule 0.002 mm. ; 

 width of endospherule 0.0012 mm.; cilia line interval, anterior 

 0.00112 mm., posterior 0.00275 mm. 



This species resembles somewhat P. tenuis and P. fllifoTmis, but 

 is smaller than they. It bears no cilia on the posterior end of the 

 body, which ends in a very sharp point, almost a spine. The nuclei 

 of this species are slenderly ellipsoid or spindle-shaped. Their his- 

 tological condition in my material is not such as to permit study of 

 the mitotic condition in detail. From their form it is probable that 

 the nuclei are in the anaphase condition. Some smaller individuals 

 are found, probably fresh from division (fig. 35, c), whose nuclei 

 are in the form of a very long slender dunib-bell, not having reached 

 the usual resting condition for the species. 



Protoo'palina africana may perhaps be regarded as an intergrad- 

 ing form between the greatly elongated species, P. tenuis and P. 

 fHiforniis.^ on the one hand, and the group of posteriorly slender- 

 pointed species, including P. xenopodos and perhaps P. nutti from 

 Afi'ica, P. diplocarya from South America, and P. acuta and P. 

 papuensis from Australasia. Protoopalina caudata form attenuata 

 from Europe approaches this group. 



