— DI7 — 
Two fresh parasites from the opossum were separated from 
surrounding tissues and crushed w ith a glass rod. The turbid con¬ 
tents were taken iip with saline solution and after several minutes 
were injectée! into the muscles of the right hind legs of two gui- 
nea pigs. 
One guinea pig after a period of 6o days was sacrificed. Upon 
dissection there were no gross évidences of infection. Sections of 
muscles of the right hind leg, examined microscopicallv, showed 
here and there a few small, intramuscular sarcosporidia, the cap¬ 
sules of which were very thin and enclosed many small sporozoi- 
tes, apparently not arranged in sporoblastic chambers. One para¬ 
site was i6 wide and 34 long;it contained sporozoites, the 
nuclei of which were 1,5 to 1,75 y in diameter. One sarcospori¬ 
dia, eut obliquely, was 33 in diameter, and contained sporozoi¬ 
tes with nuclei at one end. 
The other guinea pig was sacrificed 146 days after the inocula¬ 
tion of sporozoites from the opossum, but no sarcosporidia could 
be detected in many sections of tissue from either the right or left 
hind leg. 
The sarcosporidia found in the guinea pig’s muscle, after ino¬ 
culation with sporozoites of Sarcocystis sp. opossum, corresponds 
in morphology with the one found by the writer in the biceps of 
a negro, native of Barbados, and also with the one found in two 
ont of six guinea pigs, 164 and 183 davs after feeding with spo¬ 
rozoites of Sarcocystis mûris. 
The writer believes that this small tvpe of sarcosporidium 
should be regarded as an abortiv one, being found in an unusual 
or unaccustomed host and having a tendency to disappear from 
the tissues. In the case of the human infection, observed bv 
the writer, tissue was removed from the host on three occasions, 
and on the third the parasite had entirely disappeared. 
{The Lahoratory, Ancon, Canal Zone). 
Résumé. — Cette nouvelle Sarcosporidie, trouvée chez une 
Sarigue, se rencontrait, non-seulement dans les muscles striés 
volontaires, qui constituent son habitat ordinaire, mais encore 
dans le tissu conjonctif, les muscles lisses, le tissu glandulaire, 
le cœur. Les poumons, les parois de l’estomac, de l’intestin grêle 
et de l’œsophage, le péritoine, le péricarde, la glande sotis-maxil- 
3G 
