29 
Acaiithocephalus elegans has been found in a squirrel 
monkey (Saimiri scurius No. 5374) and another unidenti- 
fied acanthocephalus in a pale cebus (Cebus flavescens 
No. 5347). The latter is doubtless also of the same spe- 
cies as the first, but is unavailable for determination on 
account of the value, as an exhibit, of the worms attached 
to the museum specimen. These worms are about 3 cm. 
long, are deeply blood stained, the booklets of their pro- 
boscis are deeply imbedded in the colonic wall, and the 
gut wall is in places externally diverticulated and adherent 
to the neighboring stomach wall. 
Filaria gracilis has again been found twice in monkeys 
this year. Occupying a position in the peritoneal cav- 
ity as it does, treatment is not at all promising and care- 
ful search of the literature was made without finding 
any reference to its life cycle; this precludes a hygienic 
attack aimed at an interruption of it at some point. It 
appears as though the parasite is only occasionally and 
accidentally pathogenic. 
Spiroptera incerta. The droppings of 34 newly-arrived 
parrots in quarantine have failed to show any ova of this 
parasite. 
Hepaticola hepatica in prairie dogs. . This subject has 
been mentioned for several years past under the name of 
Trichosoma hepaticum, but the worm has lately been 
placed by Hall in the new genus Hepaticola. Last year 
we reported the finding of the disease in an advanced 
stage in the livers of two prairie dogs. The diagnosis was 
made in the usual way, by laparotomy after trapping the 
animals. This meant much to us because in the first 
place it showed that our first case, back in 1915, was no 
flash in the pan, but that the disease was endemic. It 
also furnished an explanation why the prairie dog popula- 
tion should decrease in spite of known frequent births, 
and emphasized, in view of the undoubted rat origin of 
the disease (1919 Report page 22), the importance of 
continuing our efforts at rat extermination. 
In the second place it gave us prairie dog material for 
feeding to rats, and we were successful in transmitting 
