of the ova of H. longior, and it seems almost certain that those authors who 
have laid stress upon this feature in their descriptions of “ H. murina ’—among 
them Dujardin himself—were dealing, as regards the ova, with //. longior. 
There remains one point of considerable interest to be mentioned. As is 
well known, the researches of Grassi and his collaborators have led to a general 
acceptance of the theory that H. nana (and this covers also H. murina") 
normally passes through the whole of its life-history in the intestine of the 
same host, its cysticercoid living in the villi of the small intestine, and not 
requiring an intermediate host. Nicoll and Minchin (1911) found in the bodv - 
cavity of one of the fleas that infest rats in this country ( Ceratophyllus 
fasciatus ) a cysticercoid, of which they observe that, unless it is that of 
“H. murina ,” it must be that of some undescribed form, the scolex of which 
is indistinguishable from that of “ H. murina ” Johnston (1913) also found 
a cysticercoid in Australia in Ceratophyllus fasciatus and another rat-flea, 
Xenopsylla cheopis, which he regarded as that of “ H. murina. Now it seems 
highly probable, bearing in mind the great similarity between the scolices of 
H. nana fraterna and H. longior , that the latter is the adult foun into which 
this cysticercoid develops, and that these cases cannot be taken as e\ idence 
that H. nana fraterna ever makes use of fleas as intermediate hosts. 
The following species of Hymenolepis are recorded in Muridae 1 : 
With armed scolex: 
Hosts 
nana fraterna Stiles, 1906 
( — Taenia murina Duj., 1845, e.p.) 
microstoma (Duj., 1845) 
contracta Janieki, 1904 
criccti Janieki, 1904 
muris-variegati Janieki, 1904 
longior, sp. n. 
With unarmed scolex: 
diminuta (Rud., 1819) 
rdicta (Zschokke, 1888) 
horrida (v. Linst., 1900) 
proccra Janieki, 1904 
Epimys rattus 
E. norvegicus 
E. alexandrinus 
Mas musculus 
M. pumilis 
Micromys minutus 
Eliomys quercinus 
Epimys rattus 
E. norvegicus 
M us musculus 
Epimys norvegicus 
Mus musculus 
Cricetus cricetus 
( C . vulgaris) 
Mus variegatus 
Epimys rattus 
E. norvegicus 
Epimys rattus 
E. norvegicus 
E. alexandrinus 
M us musculus 
Hesperomys pyrrhorhinus 
Epimys norvegicus 
? Mus musculus 
Epimys norvegicus 
Arvicola amphibius 
Scolex undescribed: 
asymrnctrica Janieki, 1904 Microtus arvalis 
crassa Janieki, 1904 Epimys iwrvegicus 
Mus musculus 
1 The descriptions of H. arvicolina, II. diminutoxdes and II. inexspectatu Cholodkovskv, 1912, 
have unfortunately proved inaccessible. The first appears to occur in Microtus arvalis (Arvicola 
campestris), the two last in Epimys norvegicus. 
