THE INTESTINAL PROTOZOA OF FROGS AND TOADS. 261 
Labbé (80) mentions that he found a parasite, like that 
occurring in newts, in the nuclei of the intestinal epithelium 
of Ranatemporaria, Without givingany further description 
he bestows the name Karyophagus ranarum n. sp. upon 
it. But onthe very next page (p. 212) he says that he believes 
that this parasiteis identical with Karyophagus salamadre 
Steinhaus and Cytophagus salamandre Steinhaus. And 
he proposes to call them all Acystis parasitica! Later 
(31) Labbé retains the name Caryophagus ranarum 
Labbé for the intestinal coccidian of the frog, but gives the 
host as Rana esculenta, and gives no further description 
of it. It is obviously useless to attach much importance to 
these names, and impossible to identify the animal. 
The only careful work which has been done upon the 
coccidian parasites of frogs is that of Laveran and Mesnil. 
But none of the forms described by them appear to corre- 
spond with my form, These two investigators have worked 
out the whole of the hfe cycle of the organism found by 
Lieberkiihn, and have discovered some very interesting details 
(Laveran et Mesnil [82]). Of special interest is the fact 
that this parasite, though normally attacking the kidneys, may 
give rise to a general infection of the host, And in such 
cases the small intestine may be infected. However, this 
animal has nothing to do with the form under consideration : 
it is an Isospora, with disporic oocyst and tetrazoic spores. 
Laveran and Mesnil described also (83) two more coccidians 
(from Rana esculenta), giving them the names Coccidium 
ranarum and Paracoccidium prevoti. The latter differs 
from all other coccidia in that the sporocyst dissolves in the 
later stages of development, so that the sporozoites come to lie 
freely in the oocyst. The former, however, presents many 
points of resemblance with my parasite. But it differs in 
several points, the most important being the absence of an 
ooeystic residuum. Quite recently Mesnil (38) has found 
another coccidium—an Isospora—in the gut of Hyla 
arborea. 
It thus appears to me certain that the parasite under 
