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No. III. 
ON AN UNSUCCESSFUL ATTEMPT TO INFECT MUS DECUMANUS 
witH HYMENOLEPIS NANA, SIEBOLD, AND ON THE 
SECTIONAL ANATOMY OF THAT PARASITE. 
By F. H. STEWART, D.Sc., Capt., 1.M.S., Hon. Assistant, 
Indian Museum. 
(Plates XXXIV—XXXV). 
The question of the specific identity or distinctness of Hy- 
menolepis nana, Siebold, and H. murina, Duj., is a matter of prac- 
tical as well as of scientific interest. Grassi, Calandruccio, and 
Rovelli (1, 2 and 3) consider that the two species are identical 
and that H. nana is only a dwarfed variety of H. murina. 
Moniez (7) and Linstow (5) have maintained on anatomical 
grounds that they are two valid species. Grassi and Rovelli (3) 
state that on feeding rats aged between one and three months 
with ripe proglottides of H. murina the contained onchospheres 
developed to cysticercoids in the intestinal villi of the rat, and 
further that the cysticercoids ultimately rupture into the lumen of 
the intestine and there become adult. They apparently did not 
attempt to infect man with the tapeworm from the rat or to 
perform the reverse experiment. Grassi (1) had previously ad- 
ministered to a boy ripe proglottides of H. nana and had found 
proof of the subsequent existence of the parasite in the bowel. 
He did not, however, consider this to be conclusive proof of direct 
transmission from man to man as Hymenolepis nana is very 
frequent in the district where the experiment took place. 
If the two species are identical and if the development in 
the rat is direct as described by Grassi and Rovelli, it is clear 
that infection in man will as a rule be due to contamination of 
food by rats. To prove or disprove the transmissibility of H. 
murina to man or of H. nana to the rat would therefore be of 
considerable practical importance. It is also clear that when 
such eminent zoologists differ on anatomical grounds as to whether 
the species are one or two, the scientific question can only be 
decided by feeding experiments. 
The experiment which the present paper records could unfor- 
tunately be conducted on a small scale only and as it proved 
negative would require to be repeated on a larger scale to be 
