8 THE COMMON RATS 



In the pages which follow however the designation Mus has 

 been retained for the rat as the older term is well understood, 

 while the new term Epimys is at present generally unfamiliar. 



The following condensed citations of the place of the original 

 descriptions with some of the associated references serve to 

 give a brief history of the nomenclature. 



MUS, Linnaeus, 1758 

 EPIMYS, Trouessart, 1881 Miller, 1910. 



norvegicus, Erxleben (1777 descr. orig.) 



decumanus, Pallas (1778). 

 aquaticus, Gessner, 1551. 



Cosmopolita; ab Asia Occident, in Europam navibus translat. et 

 inde in omnes Orbis Regiones. 



rattus, Linnaeus (1758 descr. orig.) 



Cosmopolita; ab Asia Occident., in Europam a navibus trans- 

 lat., et inde in omnes orbis regiones. 



alexandrinus. Geoffroy, (1812 (or 1829 vide Sherborn, 1897) descr. 

 orig.) 



Asia minori, Arabia, Aegyptus, Algeria, etc. 

 Italia, Hispania, Gallia merid. orient, et occid., et inde in om- 

 nes orbis regiones. 



Since attention was called to Erxleben's description in 1777 

 (Rehn, 1900) his specific name, norvegicus, as the designation 

 for the common brown or Norway rat, has been used in place of 

 decumanus (Pallas, 1778). The designation norvegicus is now 

 well established and will be used here. 



There seems no question that Mus rattus and Mus r. alexan- 

 drinus are related to one another as color varieties of the same 

 species (de 1'Isle, 1865; Millais, '05) and they are so considered 

 in the following pages. For convenience we shall use the term 

 Norway or Norway rat for Mus norvegicus and the term Rat- 

 tus or house rat as a general designation for both Mus rattus 

 rattus and M. rattus alexandrinus unless the occasion calls for 

 the precise name. 



Albinos of the house rat have without doubt existed in the 

 west of Europe at one time or another ever since this form over- 

 ran that region (Topsell, 1658) and one or more such skins as 

 well as pied skins, from animals taken within the past fifty years, 

 are in several of our United States museums. 



