578 MURIDA—EPIMYS 
effective copulation (ze. with the production of a vaginal 
bouchon), but the unions were infertile ; his friend C. Mailles 
was also unsuccessful. Iwanoff (Avch. des Sez. Biol., xii., 1907, 
376; Marshall, 609) artificially inseminated a white mouse 
with spermatozoa of a white rat; two hybrid young, inter- 
mediate in size between mice and rats, were produced after a 
pregnancy of twenty-seven days. 
Exceptional variation:—Specimens of rats and mice with 
the skin corrugated and devoid of hair have been occasionally 
reported ; for instances and references, see Proc. Zool. Soc., 
London, 1856, 38, and 1903, 336. Albinic or melanistic indi- 
viduals are not uncommon.  Tailless and other physically 
deformed rats are known, but such deformities appear usually 
to be the results of injuries. 
Two species have to be described as British, viz., the Black 
or Ship Rat (#. vattus), and the Brown or Common Rat 
(EZ. norvegicus). 
i. THE BLACK OR “SHIP Rad: 
EPIMYS RATTUS, Linneus, 
For synonymy, see below under sub-species. 
Le Rat Noir of the French: de Hausratte of the Germans. 
Terminology :—Rats (late Latin vatws and vrattus, of uncertain 
origin (1V. E. Dict.), but possibly derived from vapere (de I'Isle), radere 
(Skeat), or rodere (Cent. Dict.) ) are not mentioned in the Epznal Glossary 
(about 700 A.D.), where the word mus is applied to shrews. They 
appear first about 1000 A.D., in Archbishop AE#lfric’s Vocabulary (ed. 
Wright-Wiilcker, 1884), where vaturus=“ret.’ According to the 
New English Dictionary the word appears to have been adopted from 
the Latin first by the Teutonic languages in the form va¢/ov, and later 
by the Romance tongues; the converse view, however, has been 
advanced by de I’Isle (see p. 582), and it seems probable that prior to 
the Crusades the name was applied to the House Mouse (see p. 579). 
In the Latin writings of Giraldus Cambrensis (1147-1223) rats are 
perhaps first clearly distinguished from mice; while in the Vzszon of 
Piers Plowman (1377), B. Prol., 146 and 200, “a route of ratones. ... 
And smale mys with hem” are mentioned. Shakespeare, Zevzfes?, 
Act i., sc. 2, 147, 1610, has: “ Nor tackle, sayle, nor mast; the very rats 
instinctively have quit it”; and also Measure for Measure, Act i., sc. 2: 
“Rats that ravin down their proper bane.” 
