C. Stiuckland and U. Mkrkiman I I 
111 addition to the above it has been found by other observers on 
Mus silvaticus (long-tailed field mouse). 
Microtus aarestis (field vole). 
Myoxus nitela (garden dormouse). 
Myoxus (jlis (squirrel-tailed dormouse). 
Gricetus frumentarius (hamster). 
Mustela foina (beech martin). 
Mustela putorius (pole-cat). 
Crossarchiis fasciatus (banded mongoose). 
Arvicola savii (vole species). 
Pity my s suhterraneus. 
Canis layupus (arctic fox). 
This species, according to Chick and Martin (1911), and Martin and 
Rowland (1911), readily bites man ; and that is also our experience. 
It thrives on the rat. One of us (C. S.) has raised it with ease on the 
rat for two or three years past. 
The Indian Plague Commission found that this species in India can 
transmit plague from rat to rat {Mus rattus), two experiments having 
been successful. 
Ctenophthalmus agyrtes (TyjMopsylla agyrtes Heller, 1896) 
Wagner, 1902. 
According to Chick and Martin, and Martin and Rowland, this 
species does not bite man. It was first discovered in fair numbers on 
rats in Cambridgeshire in 1908 by Nuttall and Strickland, but it never¬ 
theless seems to be widely distributed and nowhere scarce. The rat 
would, therefore, appear to be a true host for it. With regard to its 
other hosts, we have taken it from a stoat (three specimens) and from a 
ferret (one specimen); while other observers have noted it from the 
following hosts : 
Mus musculus (mouse). 
Mus silvaticus (wood mouse). 
Evotomys ylareolus (bank vole). 
Arvicola amphihius (water vole). 
Microtus arvalis (continental field vole). 
Sorex vulgaris (common shrew). 
Crossopus cHiatus (water shrew). 
Talpa europaea (mole). 
Mustela vulgaris (weasel). 
Mustela putorius (pole-cat). 
From 822 rats 1257 fleas were taken—an average of about I'o per 
rat. We can find no correlation between the presence of plague in rats 
